It's easy to say : Go, be well, take care of yourself!!! I've heard it lots of times, from my mother even...
It's harder to follow through when you don't love yourself enough to make an effort.
I find when I try to take care of myself again, starting from scratch when I've been binge watching tv and eating junk all day, is to start by doing one good thing.
If you can do one good thing for yourself every day, maybe all it is is make yourself start going to bed at a specific time every night.
When you make going to sleep a habit, you're body might trick your mind. If you feel better from having enough sleep, then you might get up and go outside in the morning. Or you might have the energy to make breakfast, instead of just eating whatever is easy.
Another one thing you can do, is when you feel the urge to watch tv, grab a book that is really good, and read instead. Spend the same amount of time reading as you would watching tv (30 minutes, 1 hour, etc...). That is, if you like reading. This one is so good, because you don't even have to change much about what you're doing... but what changes is you don't tire your eyes, and you don't eat junk because your hands are busy turning the pages.
I hope this is vaguely helpful. It's really tough to break away from numbing habits when you feel bad about yourself, so I'm definitely not telling you to run outside or get to the gym, because those habits take more time and self love. (Once you get the sleep thing down, and the book instead of tv, then you can try walking outside every day for 20 minutes... if this cuts into your reading time, that's good! You'll probably start with a lot of reading time)
The thing about people giving you looks in the supermarket... that sucks. I'm so sorry you have to go through that. People are so compassionate towards animals and distant starving children, but they can't seem to summon compassion for their neighbors. The only thing you can do is change how you feel about yourself. Then, their looks won't matter