Problems bringing me in a funk, need sound objective advice

So I have a huge issue regarding this girl I like/care for and betrayal of friendship. Well it all started in October. I met this girl in my English 12 class who transferred in from AP Lit (like how AP Lang is the equivalent of English 11) and we peer edited a paper together and she was really nice and before long I developed a crush on her. When I realized it I got flustered and we didn't really talk after that for like a month and then our teacher changed the seating arrangement in the room and we sat right in front of each other. Gradually we started talking to each other more, although it remained somewhat erratic because of my nerves.  Finally, right before winter break, our class was in a computer lab working on something and she sat alone so near the end of class I went up and talked to her one on one. It may sound simple, but I'm really introverted with people that I don't know well, so it was a big step really. She got a boyfriend though and it put the romantic in me down, so I feared that was the end of me.  But then when I got back from break, we were talking all the time. It was just natural and I liked her for her and I was really happy, and she broke up with her boyfriend eventually (not that I wasn't before, but you understand.) But then I made a cataclysmic mistake: I tried to get her number and it failed (more specifically her Skype number). It was a error then and it remains one now. She got quieter with me after that, however I had a plan.  Her birthday was the last day of the second quarter (jan 25) and she had talked to me about how she got into her first choice for college, so I ordered a camelback bottle from the school's store to give to her. Of course though that was also the early release day due to snow and of course she skipped English that day because we were not going to do anything. So I agonized over whether I should still give it, too fast or not, all those great questions flowed through my head. Finally I gave it to her nearly a week later and...  She really liked it, and was happy and started to open up again. I was feeling better and that the worst had past and it could only get better from here, right? Wrong. Enter Tim.  If you don't know him I can sum him up like this: former friend. He figured it out (expected it at some point) and has since mercilessly tried to pull me down. Telling me how she finds me creepy and I stare at her etc. Tim is not a reputable person in the sense that he's a notorious liar and bully to others, so this isn't shocking behavior, although I'm surprised that I became his target. However it got quiet with her too and we didn't talk for nearly two weeks and even then it wasn't like before where it was real and such. And lately she's been in the library because of the research paper I mentioned (long story) and Tim keeps planting it in my head that its actually because of me. It's just driving me crazy.  Finally, somebody noticed what was going on and told on Tim for me. He apologized and admitted he went too far. However, he still claimed that she viewed me as a creep and whatnot, so I'm still skeptical of him in saying that he'll back off.  Basically with her, she doesn't seem angry or uncomfortable with me as she talks to me, but it's very quick conversation and not like before where we talked about various things freely. I don't really care about the crush anymore, I just miss the friendship I had with her and that natural sort of happiness I got with her and I hope that there is some way to bring that back.  I never ever wanted something like this to happen and if she's really been hurt by me, I wanna try to heal the wound. It's affected me negatively and put me in a funk that has brought me to my lowest in recent memory. I hope someone here has got some ideas for what I could/should do.