Broke up with longtime boyfriend

Hi, 
I broke up with my boyfriend whom I have been dating for the last five years. I was really serious  about him. At a point we were thinking about marriage, kids, and future cities had all been laid out before us. But I don’t know what happened last month. He started to maintain a distance from me. The last conversation was completely heartbreaking, and it was a day before I was set to leave town for a while to visit family. It broke my heart. While on the way to the airport, he told about his partner and I ended up punching him. I never doubted him. He cheated on me. Now I'm not able to do my works or anything. I feel like I'm completely lost. I have heard about medical marijuana treatment from a friend which is suitable for depression. Is that true? I have taken an appointment in a nearby clinic for medical marijuana. Will this medical marijuana help me out? Share your views.