I feel u...
I think ur mom was right yo make u break up with him but I don't think she should have grounded u bc it's not ur falt

But I don't think you deserve hime bc he had a crush on someone else so it's better off u find someone that loves u even more and fingers crossed they won't ruin ur mental health

I'm kinda suffering from the same thing but WAYYY milder.. my gf broke up with me a few years ago
And I still love her to pieces but I think ik why she broke up with me cuz we were EXSREMELY yound so we took a brake, she is in my school and man I love her so much I'm obepseseed and j swear I have dreams of her every single night, but I really hope u get better and ur mental health
-Leela <3