@LemonWeep43
Im very sorry about your sister, and that you feel like that. But asking for help is a good step. please remember, there's no shame in contacting a professional - I deeply encourage you to, as soon as you can. your life is special whether you think it or not. if you need help getting out of a rough situation, and feel alone, please, please remember you aren't, and you aren't destined to be alone.
But even if you feel that way, you can get yourself out of the pain, or at least shape yourself to be more prepared to deal with. And it starts with looking for help. putting in effort. it can be small, like beginning to surround yourself with good things. things that make you feel a little happy. (personally I have a YouTube playlist called "things that bring me joy" and it's a bunch of animal videos I would die for.) if you find the little things in every day life, and focus on them, you'll slowly start to feel at least a little bit better over time. personally I think getting out of a painful situation is time, and a positive mindset. if you put yourself down, and if you only focus on the negatives, you won't notice the good things, and you may not improve as effectively.
but everyone is different. some people benefit from walks in nature. some don't. (but I promise, very few people actually benefit from staying up. sleep is so utterly overlooked when it comes to mood and mental state. don't sleep in too much, don't stay up too much. I swear by good sleep schedule = good day.)
(comment too long, there's a continuation)