I get it. Have you tried setting some ridiculous small goals involving self-care? If what you're doing is scrolling social media and watching youtube, maybe set the phone or computer or whatever aside and eat something healthy. Take a shower in a way you WANT to do it (personally, when I have access to it, I like using a nice scrub like Dr. Teal's and listen to some music). Brush your teeth, reminding yourself it's just a two minute thing that you are completely capable of. You don't have to do all these things at once.
Take it slow, focus on the small things/the very basics of self-care. But you need to start by ending the scrolling and videos. You won't be missing out on anything, and it'll always be there later.