I can well imagine this. But it also might be a good opportunity. Can you find a mentor outside the institution or make them pay for external coaching?
Can you change the system - with backup, eg from a steering committee? Might EDI help- the system you describe sounds like it conspicuously disadvantages women and junior staff.
If nothing else, now you get the chance to redistribute labour fairly and model a better system. The old buffers/ young dogs may hate this but ultimately you're the boss.

Sounds like you know what needs to be done. Stop being the good girl, make a plan, and off you go. Give yourself 2 years. You have a chance to change the way things are done and you can clearly see what the problems are.

Do you have any allies at all in the staff? Anyone you moan with about unequal allocation of work? I’m wondering if you can talk to a few people before hand and plan eg bringing in workload models and actually trying to make a few changes

"Can you change the system - with backup, eg from a steering committee? Might EDI help- the system you describe sounds like it conspicuously disadvantages women and junior staff. If nothing else, now you get the chance to redistribute labour fairly and model a better system. The old buffers/ young dogs may hate this but ultimately you're the boss."

The latter is not true. The HoD role is temporary and correspondingly the HoD is not viewed as a boss by senior staff. It is very difficult to make large charges particularly if the HoD is considered to be less senior than senior professors within the department. (And she is not yet a professor.)Those who have special deals will protect them by going above the HoD, working with each other and generally making the life of the HoD difficult.

I think bigkidsdidit is correct about looking for allies amongst the staff. If there are enough people who want change then it may be possible to make some progress, particularly if the people above the HoD are supportive. For example a decent workload model is essential for Athena SWAN - but the Athena SWAN panels don't actually check whether the department actually operates the model they claim. Many departments that apparently have detailed workload models still give special deals to the favored few.

Interestingly, there were 3 other people who were eligible to be HoD, and they refused to even consider it from the beginning but apparently they aren't uncollegial, only I am

You were manipulated into taking on a stressful and difficult job, while others were given a free pass. This suggests that the people around and above you are not going to be supportive. Personally I would run a mile & cite family/health reasons for not being able to do the job.

sorry that this has happened to you. the depressing thing in academia - is that unlike in other places where such responsibility would come with a genuine promotion, here you just get more admin and more angst. Being a HoD wouldnt be so bad if they paid you 1/3 to 1/2 more but that never happens. Thats why I would never do it, literally no incentives in doing it. sorry that you got lumbered with it

If you are not getting a reduction in teaching, or money, or promotion, you should not be doing this whatsoever, for your mental health and sanity. I would go to the drs, then OH, and then withdraw. They will be in the shit, but you won't get any of the things you need from this, and a lot of ire, anger and powerplay for nothing. In our department you would at least get a teaching reduction. Don't 'be nice' to the detriment of your own mental health and career prospects.

As for being the boss, I have senior colleagues who would rather get the lawyers in (as they do if there are any complaints/changes to their working arrangements) than do extra work. I wouldn't be a junior (to them) implementing a new workload model for anything.

Teaching should be absolutely minimal. I take the point about who's the boss- and managing from a junior position is very hard too. Is there anyone on senior management interested in equity? Is there a women's network? There's a leadership programme for women that might be helpful.

if you are not getting a reduction in teaching or a pay rise or a promotion you are mad to do it. Sorry - not trying to be harsh. But really! I would have taken it if they were desperate because I don’t like disappointing people but absolutely I would have negotiated to hand all my teaching over and to get a prof app in the next promotion round.

I would go back to the current head and say with your mental health as it is you can’t do this role and teaching (this is probably true / you will work yourself into the ground doing both). Ask which one they want you to do. And mean it!

You should use your unsuccessful (partially) promotion as a way of getting out of this. Say that you are obviously (by the university’s own evaluation) not in a position to step back from your research and other promotable activity for three years. I’ve been doing a HoD job for the last year, and it’s a disaster as far as promotion goes. There’s bugger all in the role that counts for promotion and my research is screwed (I’ve managed three days in the last year) as my time is consumed by endless meetings and firefighting.

O would ask for an external mentor AND an external executive coach and try to find allies. Good luck. It is SHIT!

My choice would be to cancel some of the options courses and redistribute the students among the options as best as we can

I would absolutely do this.

@aridapricot if you go off sick or have a huge downward lurch in MH then this will inconvenience students much more. I would take action now to prevent this happening. Either get the teaching covered elsewhere by temp staff like everywhere else has to do, agreed at the appropriate or remove yourself from the job which is what I would do. I would say my circumstances/MH has changed and I'm no longer able to do it. You sound sick with anxiety already.

Your work cannot make you do extra teaching if you are the HoD and allocating workload! Your work cannot make you be HoD if your circumstances change/MH concerns will not allow it. You can get signed off, take sick leave, or get an occupational health assessment which should establish a limit on working duties. You are driving yourself to do these things out of a sense of obligation, legally there isn't a mechanism for enforcing this against you, which leaves you more in charge of your destiny than you think...

it may be that the role has some leverage for promotion where you work. In my case, the university has very clearly-set out criteria for promotion, and the work I’m doing as a HoD does not accrue any points, except for line management (and, then, not enough for a promotion). I was actually promoted to Reader at the point when I was considering the HoD role and, if the promotion had been denied, I’d absolutely have refused to take on the HoD role. As it is, I’m pretty fucked off that I’ll lose three years that could have been put towards activity leading to a professorship, and am considering stepping down before the end of my term (though there are other reasons for considering that too).

It sounds like you’re in a terrible place mentally. You should absolutely step down. In these situations, a more senior member of the department should step up.

HoD would definitely count for promotion where I have worked but would not necessarily be enough to offset a weaker research portfolio. If you have the support on the panel, then HoD could set you ahead - it could be a "reward". But this does not always happen - in my experience, it's often not the HoD who've done the best job that get rewarded in promotion panels, but those with supporters on the panel.

I appreciate the difficulties in filling gaps in teaching but I think female HoD often do make the mistake of sacrificing themselves, instead of holding their ground and not doing the work themselves. I would cancel options and/or insist on funding for somebody to teach these options. You are almost never rewarded for taking on additional work that doesn't result in clear kudos for your personally e.g. grant income.

Under no circumstances do the teaching! That sets a tone that says 'If no one else can/will do it, HoD will step up.' If you don't protect your time, no one else will. You must claim such authority as you have.

We constantly tell students that their MH is the most important thing and if they need to step back that's fine. Ultimately that's true for you, too.

But is it possible that some of your worries are premature? I realise you've been suckered for years (as have I). Nevertheless most people are focused on themselves and don't like to acknowledge that their selfishness means screwing over others. Is it possible that, as with most of us, most people don't give you much unnecessary thought at all? That would be a fine thing, because your expectation that you can't exert authority with them would have no basis in fact. If you're going to step into the HoD position, can you use this idea to gain some confidence?

Finally, and I don't mean to be facetious, I think the most successful women I know would find a way to say, essentially, "if I am going to take this role it needs to work for me as well as for the Department. I realise I didn't give enough thought to that. As things stand I have some significant concerns. Can we explore this further?" I haven't put that well, because I am not one of those women. But maybe it's worth considering whether you can do this?

Absolutely this

You don't want to do it, so don't! It is absolutely not in your own best interests and you probably won't even be there much longer.

A man in your position would say no. Women are socialised to be nice, we need to stop going along with it.