my crush likes my bestfriend

(so before i start with my paragraph. i know that i can’t change what he feels, i know that i can’t make him like me. and i’m okay with that) i’ve likes this guy for about 9 months now. he’s one of my best friends, he’s funny, kind and such a good friend. i grew some balls and gathered up some courage to tell him my feelings. i have anxiety and depression, so i was having multiple panic attacks while waiting for him to message back. 3 hours of crying and freaking out in my bedroom later, he messages back, very nicely letting me down, that we are still close friends. i of course was disappointed and started panicking about my weight, looks, voice, additive, everything you could possibly worry about yourself. i had already been self harming so i cut up my leg pretty bad. he has this massive crush on my bestfriend, and she told me she doesn’t like him back. but i feel like she does in a way. i invited them both to my birthday party today, and they are hanging out just the two of them and been hanging for an hour. i get that i can’t change that he likes her, and if she likes him. but it breaks my heart to know that he likes her. every time i see them together i want to cry. i’ve been depressed this entire birthday party, i’ve cried 2 times, no idea why. but i don’t know what to do. i like him so much. so fucking much and i can’t bare with the fact that he doesn’t like me back:(