How to get over a breakup?

Two Saturdays ago my boyfriend broke up with me. We didn't talk for about 4 days afterwards and then he came to my place to ask for another chance. So we started talking and stuff again and everything was fine, till yesterday. He blocked me everywhere and hasn't answer my calls. He was my first boyfriend and we lasted for about 3 years. I'm so depressed right now. He was my everything since I gave up all my friends for him. I don't know what to do.