The one and only friend I ever felt truly understood me abandoned me 2 months ago and I'm still non-functional to this day

For the first time in my life I found someone that understood me, a friend I could be myself with without needing to keep up a mask or carefully filter what I said

Then at some point I became so morbidly attached to them to the point where them doing things with other people would make me irrationally passive aggressive towards them, and 2 months ago they just had enough and decided to cut me out of their life, I just couldn't let it go and kept trying to ask for their forgiveness until eventually they felt like the only solution was completely blocking me out of their life wherever they could

It's been 2 months since this thing started and I've been pretty much non-functional through it all, haven't done anything but work and cry at home (and sometimes at work too), I just can't bring myself to do anything, and the only way I see out of this is this person eventually deciding to forgive me and give me another chance to be better, but there's literally no reason whatsoever to think that's ever going to happen, from the little of their life I can see through public profiles their life didn't stop for a moment, I doubt they even still think of me at all

I'm just so tired of feeling like this but not even therapy is helping at all at this point