How do i get over her?

So im going to start off by saying that i am an asshole. At least to her i was. So i was in a relationship with a girl for about 3 months and she was perfect, at least to me she was. She was everything i wanted and more and i was at the happiest point in my life. Well the problem was that i didn't know what i wanted from the relationship or if we could last so for the first two 1/2 months i was kind of just enjoying my time with her. And yes she was enjoying it too, but eventually she wanted more, and i didnt realize it in time. I began to pressure her into doing things she didn't want to do and being the idiot i am i didn't think of how much stress or i guess uncomfortableness (is that a word?) it put on her. But she's a strong girl and she eventually drew the line and i didn't cross it.
As the relationship was entering it's third month i started feeling different. I began to realize how much she meant to me and while love is a touchy subject at this age i know that i fell in love with her at that time. I finally knew what i wanted in this relationship, a serious commitment to her and to her only that at least could last until the end of graduation. That same week i made the worst mistake of my life so far, i pressured her once more and while she let me go a little bit the line was drawn again. However that day she gave no indication that she was uncomfortable at all so i believed that it was another day of our relationship. Over that weekend i didn't talk to her at all and on the following monday she told me our relationship was over. She said that she didnt know who she was and that she couldn't handle a relationship at the moment. This made me so confused and feel like hell because i had finally realized how i felt about her only to have it be taken away almost immediately. My feelings of anger and confusion towards her went away last week when i found out that she had gone back to her boyfriend from a year ago.
After i found this out i have had big feelings of disappointment and depression, not towards her but towards myself. I am a huge believer in karma and i think i deserve all of these feelings because i had the perfect girl and i threw her away because i was too impatient and couldnt just enjoy our time together. I noticed that in the last week he has made her happier than i did in 3 months. I am also a believer in second chances and this is his second chance with her, and i think they actually look really good together so i have no ill will towards them. What i want to know is how do i get over this? i graduate in three 1/2 months and i just want to survive with my sanity until then and stop feeling like a failure even though it was my fault.

For future reference: if you have to pressure someone to do something then they ARE uncomfortable. It's not rocket science.

You get over it by learning from your mistakes. Realising that she's not the only girl in the world. And not making the same mistake twice.

You get a life and go out with other girls.