Depression frustration. More frustrate!

I'm having depression and frustration after my breakup. I had a breakup 3 years back then I thought I could never believe in love. Then when I finally moved on from him after 2.5 years. Someone at whom I got crush, I never believed I would ever feel the same feelings again. That person cheated on me lied to me in these 4 months that person only made me cry, bcz I knew I was not the only one that person is talking to. I'm crying every second of the day, im was going to hang myself till death. I'm not able to take this pain again. Second of all I'm afraid that I'll go to college as my ex is the topper of our class and the people who are hitting on my ex, they'll create a group, I'll feel more depressed. Thinking of this makings me cry. Mainly I can't focus on my studies and my academics is very important I want to show everyone I'm not less, and I need to make my career this is my peak point. Bt during the class I sit and feel down seeing them enjoy, and I can't focus. m more frustrate