I know you said no need to reply, but I am anyway as I think this is a very important point.
I think if you're in this situation and you have other demands on your time; other kids, a full time job etc, it is nigh on impossible to carve out time for yourself. If you can though, try and just take 15 minutes a day. Even if it's locking yourself in the bathroom and running the filling the bath. I don't always get in, but I sit on the side with my feet plunged in, just breathing. It makes me feel a lot better.
Also, you're right to add notes/ feelings etc to a journal. I keep a health journal (I have to as I have to monitor pain and other levels) There have been a few times where I've just scrawled "Fuck this. Fuck this shit" all over the page. It helps me identify when it's becoming too much for me as I'm Autistic and It's imperative that I notice if a shutdown or burnout is brewing.
I'm (sort of) lucky in a way as I only have DD, but I'm a single parent and I'm disabled. Due to this, I now work VERY part time. I learned my lesson by physically and mentally wrecking myself over 33 years of demanding work. Yes, I had to adjust and re jig things financially, but I'd paid off my mortgage so it was doable.
My main thing is having just five minutes after getting home. Before I deal with dinner / feeding the cat / questions / issues etc, I just have that five minutes every day. I've built it in over the course of the last couple of years. I shout to DD that I'm 'having my five minutes' and I go and stand in the garden. She knows she can ask me stuff after that (and she does, it's literally questions every 10 minutes until bedtime at 10pm - I can't ever watch anything on telly with out having to press the pause button a dozen times - but she can't help it as shes AuDHD. She does try) That five minutes let's me go OK, here wr go..
I also try and grab an hour or so to myself on a Saturday and Sunday morning. Usually before she gets up. I wake up early and savour a bit of quiet time, just reading. Even if its stuff on MN. We do stuff together on a Sunday and try and fail to do some school work, but I manage to get us out an into town, even though it ends up costing me.
My Mum is in hospital at the minute, but likely to be discharged in the next few days. I've been honest and said I'm not in a position to care for her, so OT assessment / Physios etc need to be put in place. Years ago, I'd have been a martyr and tried to do it all and burned out.