Most Helpful Guy
I've been there before. The main thing is to cut off contact with the person. Try not to let that person know that whatever happened didn't effect you. Once you do that, you can start focusing on things that interests you. Start to focus on school (if you are in school) and accomplishing your goals. Last thing is to start dating people. Dating somone new will definitely help get over someone, and do exciting things with him/her.
Most Helpful Girl
Time mostly. Spend time with people who love and care about you and let your heart heal.