What should I do....... please help

I am in a very complicated situation.

I started talking to a guy 1.5 years ago. We used to be classmates when we were kids... We were in each other's social medias all these years but we started talking on phone calls 1.5 yers ago. It was the time when I just had a serious break up. He used to calm me down, talk to me so that I don't feel lonely and gradually we became best friends. We used to talk everyday for hours, play games together and stuffz. One day he told me he have feelings for me and want me to be his girlfriend. I wasn't completely over my previous relation yet as it was pretty serious and even sometimes used to have panick attacks for my past. I told this guy to wait for me for sometime as I didn't want to get into another relation before recovering fully. But he said he can't but can't leave me too as he loves me very much. I had a lot of argument but at the end it didn't work out. He left me heartbroken again. After somedays he came back and said, 'ok I'm ready to wait as I can't forget you' ...but I was angry to him for leaving me...so I didn't agree...(I do regret that very much)

He was so sad and said it's ok. After that day he started avoiding me as much as possible. I don't have much friends. So I was totally heartbroken when he even stopped talking...just used to reply to my messages at too in a rude way. We were friends but like some stranger friends. I still adore him as much as when we were best friends and want that friendship back.

Recently he became very good friend of one of my girl best friends(Riya) and riya for some reason started talking less to me. Yesterday some of the friends we went to beach and I saw them being really close, walking, sitting laughing together. I don't know why, but I felt so so devastated seeing him close to another girl.

I am unable to sleep, eat or do anything. I'm having frequent panick attacks, those sights from yesterday is all i can see in front of my eyes 24x7 .... I'm feeling sick. I think I do have feelings for him which I couldn't realize. I want to confess him but I can't find the courage. Also I think riya started having feelings for him. If they both like each other this confession might ruin their relation & I don't want that. And if he blocks me after i confess my feelings I'll be dead.......still I'm dying inside and want to express my feelings. Please tell me what should I do?!