Bear with me, this could be long! I'd really appreciate views on whether I'm losing the plot or not...
back ground info 
Am a single parent to one ds who is 10. We live in the south east in privately rented accom. Last year I gave up my NHS job for a related job in higher ed. The NHS job was 30 hours per week, but shift work, nights, on calls etc and as a single parent it was becoming unmanageable. I was feeling terrible about shipping ds off for overnighters at least twice a week etc, having such random hours etc. Plus, I was working in a team that was appallingly managed and that was a source of stress +++
The upsides were that the money, some months, could be good (if I got lots of callouts, nights etc). Having time off during the week was very handy. And, at the time, ds was able to spend weekends with his dad and gf which took some of the pressure off.
Anyway, at the end of last year I was offered a job in higher ed, 37hr a week, no weekends, no on calls etc. Since I'm also doing an MSc at that university, it seemed like a no brainer. I also knew loads of the staff etc.' settled in quite easily. But actually, I hate it. Hate the politics (worse than the NHS!!)' hate being in an office, have been thrown into teaching BSc students without any training, find it really difficult. Most of my colleagues are lovely but the job just isn't for me. Im not the only one, either - since I've been there we have lost 4 members of what was already a small overstretched team. Plus, if you factor in the travel, extra hours etc I'm actually worse off every month, money wise.
And now... Ds's father has split with his gf and gone off the rails, alcoholic, utterly unreliable and useless. My mother who lives nearby has serious mental health issues and has taken to turning up on my doorstep at 4am. I need to be able to spend more time with her and get her (and my dad) the help they need. And I have an MSc assignment due in two weeks that I've not even thought about!
Basically, it's all too much. I am totally aware of my responsibilities to ds, to keep a roof over our heads etc, but something's got to give. I have considered agency work, which pays well and I could have a bit of control over. Also my old Trust is always looking for bank staff. I could get work there. I just want some control, and some flexibility. But I have a stable job with supposedly good prospects. I wouldn't be able to carry on my MSc if I bailed on this job. I'm just miserable, really, and desperately looking for solutions. I want to leave this job, but would that be total madness?
I don't know what to do for the best.