Break up question .....

okay so normally I hate sappy break up crap online but here I am in a moment of weakness blabbing my personal life to strangers. Anyhow my boyfriend broke up with me after a year and a half. We fought often but love each other he just feels long term he won’t be happy which I have thought about many of times on my end but I love him to death and always sucked up any negative thoughts or feelings. Anyhow I have been really upset for about a month now balling my eyes out like a girl on more then one occasion. I can’t deal with the thought of him having sex with another person. That is what is killing me. I mean I am a mess all day wondering what he is doing or who he is talking to. If I call and he doesn’t answer I get ten times worse. My heart races and I feel kinda sick. What should I do!!!?!?