Think I need to take sick leave but really worried

[Shwish]

So I've been on annual leave for Christmas and the beginning of Jan. Was meant to go back yesterday but contacted my boss and asked if I could extend my leave by a day to return Monday. That was agreed. All good.
Unfortunately I woke up yesterday with what I assume is flu. There's a lot of it about and I genuinely feel awful. Fever, cough, worst headache ever. Like can't get out of bed awful. Has anyone had this recently and were you able to go back to work by the 4th day?
If not then I think I will have to call in sick. We have hybrid so theoretically I could WFH and not worry about infecting anyone but honestly today even typing this is a massive effort and I really don't think I'm up to it.
But I'm aware that this looks absolutely awful on the back of a period of extended annual leave.
Also this year I've taken more sick leave than probably the entire rest of my working life as I had pneumonia last Feb and then a complicated wisdom tooth extraction in May. Meaning I've had I think 9 sick days since last Jan 😕.
Help. What do I do?.other than pray for a miraculous recovery by Monday.
If you were my boss would you fire me?

Sorry you’re feeling so poorly and then have your anxiety about work on top of it. I wouldn’t fire you and I’d be surprised if your boss could/would. It all depends on what your work policy/contract says though.
You might be well enough to work from home on Monday, who knows, but try not to worry too much about being ill after taking annual leave. Illness happens when it happens, regardless of what day it is!

I think if you properly rest now you’ll probably be able to work from home by Monday. You can’t help being ill though, it’s just one of those things. Feel better soon.

Lots of fluids, sleep and cold and flu capsules and see how you feel Sunday evening.

What's your sickness policy at work? After that amount we'd move to stage one but you wouldn't be sacked they need to go through the stages. I had flu for two weeks in October on the back of a holiday. My work knew I was genuinely ill, I tried to go in after the first week and they sent me home within 5 mins when they seen me. Wev had people not come back after Xmas yet who have the flu/virus like flu going round it's absolutely rife round here.

I actually don't know what the policy is if I'm honest. I agree 9 days is bloody loads and if I was too ill Monday that's even worse. I've been at my company 5 and a half years and other than this year I think I've never had more than a day or 2 - I have young kids so we've had a few sickness bugs go round.
The wisdom teeth time off was pre-arranged with work though so maybe that will be looked at differently? And I got signed off when I had pneumonia I think. I remember the doctor asking me if I needed a note, but I can't actually remember if I said yes. I think I must have though or it would have been a problem.

Rest and see how you feel on Monday. Could you get away with WFH for a few days? 3 periods of sickness within a year is a lot and it would trigger certain procedures in most work places but nobody would fire you esp if you have been a good employee and been there for so long. In the end, if you are ill you and if you have flu, it will not be over by Monday. Going back to work too soon may just make the recovery a lot longer and there are no winners. See how you feel on Monday and if rough, just let the boss know. It happens. Don't overthink it. No point in forcing it esp as you had pneumonia fairly recently. You wouldn't want to risk a repeat!

9 days isn’t that much over a year, people have much longer off at times over their career.

This wouldn’t be a problem at my organisation, if you are ill you are ill! You can’t help it!

Stay off until you feel able to work and when you do feel a little better WFH so you don’t risk taking it in to work and infecting others. Hope you feel better soon.

I'd be very surprised if no one else in your team/organisation had flu or some rotten cold at the moment as there are so many people off sick, so it's unlikely to be a surprise to your manager. In my organisation no one would think anything of it, particularly as one of your absence periods was a prearranged medical reason, but all organisations differ.
Does the manager pick up messages over the weekend? I'd be tempted to pre-empt by messaging to say something like "just to let you know, I've come down with full-blown flu - fever, headaches, achy muscles. I'm hoping to be fit to work on Monday but, given I'm likely to be infectious still, I take it you would prefer me to work from home rather than infect the test of the team!"

My default isn’t to assume people are faking being unwell. If I were your manager I’d just hope you got better and wouldn’t want you making us ill.

I've just been off for 6 weeks with a flu virus /chest infection.
All you need to do is follow your companies sickness policy (ours allows us to 'whatsapp' our manager') then its 7 days self certify (including weekends and Bank Holidays regardless of whether you work these or not) and after that you would need a dated fit note from your gp.

Thanks for your thoughts everyone. I'm pleased to say I'm feeling a bit better today. Been up out of bed since mid morning. I think I'll be able to WFH tomorrow if I can rearrange meetings to later in the week. Phew.