I got played

Warning: this is kinda long

I am a sophomore in high school and this is a story about me and this girl I met. We had the same classes and started taking a lot. I wanted to get closer to her, and I felt like she wanted to know me better too. We would talk in class and call each other after school. I've always liked boys so I brushed away the thought that I liked her. She would tell me pickup lines, and I would laugh and joke around with her. I felt that she liked me but since I never had experience with this stuff, I told myself not. One day on the phone, she asked me if I liked anyone. I told her I was confused of what I felt. She asked who and I told her it was her. She then tweeted I hate when people start thinking you have feelings for them just by being nice to them. She told me she didn't feel the same way. I was torn down. I realized I really did like her. I told myself this wouldn't work out. We got distant, but around 2 weeks later, she came to me and said I really like you, I was denying my feelings for you. Do you want to have a thing with me? I couldn't believe it. I thought she was just playing with my feelings. I asked her "are you serious?" Then she said yes and held my hand. I told her to give me some time. I thought about it then made a decision to say yes. We were doing great after that. We would show affection and it was all great. She wanted to keep it secretive so not a lot of people knew. Then one day, she came up to my friends ( they knew about us) and told them I'm ending it, finally. Then she messaged me saying I should've not pushed it. I see each other as friends. I was shocked of the fact not only that she ended it through text, but played me twice. I keep thinking she wanted to make it secretive so that not a lot of people would k so when she ended it. Now we don't talk. Unfortunately, we were put in the same group and we would have to do our assignments and projects together. What should I do? What do you guys think about this?