So many people have mentioned weight and weight loss but even if at a heavy enormous weight, you can and should still take care of yourself.
On "my 600lb life" there were a few women who still did their hair and nails even at 600lb and bed bound. Yes they are extreme examples but just because you are fat or bigger than you would like to be, does not mean that you are not worth any time and effort and self care.
Op, dig deep to change your mindset as you will feel better and then will find it easier to keep on doing it for yourself.
Find one thing you want to do and do it.
Like anything the first time is the worst but it gets better and easier.
Make a plan and even if you only stick to 10% of it, then that's an achievement as it is 10% more than before.
I know it's hard as I suffer from depression and ocd (also have an asd daughter who stopped sleeping at age 2 and is now 21, my second daughter didn't sleep till she was 4 and is still rubbish at age 10, 11 in 2 weeks but is affected by her sister) but the first things I do when able is self care as I know it is worth it and helps me in the longterm.
This week I only painted my toenails and stuck to my nighttime skincare routine. That ok and thats my achievement.
I'm also trying to make better food choices but hey ho that is a lifetime thing. I will not diet as no point, I will only make healthy changes that I will keep on doing for the rest of my life.
I hope you find your way through this op.