Why the hell she do this to me? What the hell should i do?

Damn i got a long story of problems with this girl. But before i start let me just make it known.. ive never had a girlfriend so im very vulnerable. Well yeah theres this girl i was talkin to for a while about 3 months and then i went to mexico for a couple of months but when i got back school started and i took her out to lunch for the first time like around the first week of september. that day a bunch of her friends were telling me she really liked me so i decided id ask her out the next week. the exact day i was goin to ask her another guy beat me to it. They went out for a week and like the 6th day i told her i was in love with her (i fell so easily) and she told me she loved me back and so her boyfriend told her he loved her and she said she didnt love him (he knew about me so he dumped her. the same day he dumped her he hooked up with another girl.) so i asked her out a couple days later and she said she wanted more time since she was really hurt and realized anyone could lie to her about loving her. so i waited 2 weeks. asked her out again and said she wanted more time. i started thinking she didnt love me no more.. and then last week i felt we were progressing a lot so i asked her out again last friday. she said no she didnt want a boyfriend yet. i got unpatient and told her i didnt wanna talk to her anymore becuz shes been hurting me a lot. so the next day she calls me and says i made her cry in public when i told her i didnt wanna talk to her anymore and she cried herself to sleep. i didnt believe her so i just kept talkin back to her saying stuff like u dont know how much uve hurt me ive cried myself to sleep a lot more than once. she started crying on the phone and told me to call her later. i called her 2 hours later becuz i was feeling so guilty. i apologized and she told me to not apologize because shes been acting like a real ***** to me. so i asked her what did she wanna do and she said to keep talking and i asked her how much longer she wants to wait. and she said this week. Well today shes been actin pretty stupid with me. i was texting her and i asked her out to lunch and said no because she had a date so i was like what the **** and she responded with "haha just kidding" and i didnt think it was funny and i asked her if she really liked me or if she was just going to hook up with me out of pitty. she responded with "its not that its just that youre not as attractive as michael phelps" (shes obsessed with him) and i said please im trying to be serious stop messing around and she was trying to be funny by saying "thats what she said" and so i got really mad but said "please im not trying to start a fight why are u acting like this?" she didnt respond. i saw her after school and walked up to her and just said why were u acting like that earlier? and she just stared at me for a minute straight with no words and then said "ill talk to you later" and walked away. she sent me a text message like 5 min later saying "im so sorry but i dont think we could get together.. i dont think it would work out".. so now im really mad!! i dont know what the hell to do.. im so confused any advice?