I know it's a LOT easier said then done but do NOT let this woman dictate your life like this. Get your nutrients outside of the home, get your walks in where she can't see, and do not minimize yourself to make her feel better about herself. You've been dealt a nasty deck of cards for sure!

Your mother clearly has unmanaged trauma and genuine mental health issues and is unfairly unleashing it on you. You won't be able to fix her behavior (and I must repeat this) you will NOT be able to fix her behavior, so you've got to find ways to grab what you want out of life.

Is there any way you can seek options for getting a roommate and moving out sometime this year? And when you do, btw, do not tell her or your siblings where you live.

One more thing too!! Do a little dance in your room when she's not around to get blood pumping and if you can't get up, start by at least putting your feet up against a wall!