How do i even say this..

The person i considered my best friend... the one i fell for once but eventually got over it.. now likes my other close friend. And why do i even feel that sharp pain in my heart, in my stomach? I thought i got over it. I thought i didnt like him anymore, more than a friend. But that feeling stuck, at least an ounce of it, to me. And now, knowing he likes my other close friend, and she likes him back... makes me feel like ill always just be the mediator between things and situations. It makes me feel like im just a tool people use to feel better and get advice from. But i cant just distance myself from them because it hurts even more.
I started doing some bad things to forget. Drinking, smoking, i feel guilty of it all. But i also feel like it would be better if i just idfk.. left the friend group? It makes me cry just when i think of loosing my friends. But as I said before, my two closest friends liking eachother... but still not officially being together since they're in the same friend group.. hurts me so much...

I cant even vent or rant to anybody else because i have started to feel less safe (emotionally) with my friends. Does it make sense what im saying here? Like im happy for them.. maybe this was how it is supposed to go. Maybe this is just my fate, and i have to see whats next. But it hurts.. and i cry every night to myself.. i feel sick. In my stomach. The worst part is playing it all chill when we hang out.