My girlfriend,whom I'm very in love with, broke up with me...what should I do?

Well… I never thought I would resort to this. Talking to strangers over the internet about my problems, what in the world have I gotten myself into? My girlfriend of 1 year 3 months and 12 days recently broke up with me. It has been driving me absolutely insane, and I mean that quite literally. I see her every day at school and seeing her makes me happy, but then she leaves. And when she leaves it’s like every single wound opens back up. She still has me come over sometimes and I even ended up staying the night at her house until 6:30am a couple of weekends ago (after we had broken up). It started out with us flirting…heavily… We both were so extremely happy and you could tell. She was happier than I’ve seen her in the past few months and we both were acting like we were six. Constantly giggling about every little thing and smiling at something as little as making eye contact. Eventually the kissing started, and that led to several…well…make outs. She told me that night that the reason she kissing me and acting like she was dating me was because she was listening to the way she felt more than the “advice” her “friends” were giving her (her friends were trying to get her to break up with me even though her best friend, who is like a brother to her, is now upset at her for it). I was happy for that night and that next day, but then Monday hit. When we got to school she acted as if nothing even happened. She went right back to ignoring me and flirting around with other guys. The thing that bugs me the most is this guy named Andy that she flirts with heavily. She hung out with him quite often even when we WERE dating and I even caught them alone at her house one night, but I know nothing happened. My point is that he has been trying to get with her since this school year started and he is one of my old friends. I know darn well that he is only trying to get with her for one reason…and love is not involved…he wants a get in and get out relationship. I don’t know what to do anymore because she tells me I cause too much stress in her life and she doesn’t want me back, but at the same time her cousin says she has no doubt that my ex still loves me and wants to be with me. I think most of the stress is her so called “friends” who say she shouldn’t be with me. I think it’s funny that she was completely happy with the relationship up until this school year hit. During both summers we were together she was happy with me and spoke often of being SURE we were meant to be. I think, honestly, that she needs a new group of friends if they are going to force her away from someone who cares about her as much as I do. Everyone says we are “meant to be” and will eventually get back together, but I don’t know what I should do. I’m so confused and I am literally going insane. God pulled me to this girl for a reason, and I can honestly say I am IN love with her. People say that it is because of her age (she is a freshman) that she doesn’t want to be with me and that she will eventually grow up and take me back. Should I hold on to my feelings for her? I can’t even SEE myself with another girl. This one has me hooked…deep. And another thing… she is in to the whole “grind dancing” thing with guys…thanks to her so called friends that take her to parties… and I know the image that is putting out for her. Several guys have already asked her for lap dances. She is letting her friends dig her a hole… but anyways, that coupled with the fact of how far I mistakenly let things go with us make me fear that she is going to find it very easy to sleep with any guy she gets with next. She tried to get me to have sex, but I told her no…for 40 minutes straight…and I know darn well that the other guys who want to “date” her don’t care about her enough to say “no” like I did. I’m extremely worried about her. At my age I’m ready for a serious relationship and I feel like she is the one. I was a little controlling during our relationship…and she didn’t like that… but she never invited me to her friends “parties”, she hung out with her ex without inviting me…and sometimes without even telling me since he was at the parties… and she hung out with a lot of other guys… so I was scared and a little controlling. On top of that I got really mad when I found out the provocative way she was dancing with other guys. I’m sorry I’m ranting…but there is a lot to say… I know that most couples have to try to make time to hang out with friends…even though they would rather be with each other… but I was the only one who felt that way. Were my feelings false? Is there someone better out there for me like my parents say? Or is it like my youth pastor says where my ex and I might break up several times, because she just isn’t sure, before we get married? There is sooooo much more to the story than this really long paragraph. I know what you’re thinking, “oh it’s just another over dramatic teen”, but even my youth pastor sees the way I feel about her… The way we were together. The first words out of his mouth when he found out we broke up were “you’ve got to be kidding me!!!” I’m sorry…I’ll stop ranting now. If you want more info…just ask. Trust me…I don’t do much but sit at home now anyways =/. I’m scared, I’m confused, and so many other things. Please…PLEASE help me.