Is it normal to fall in love with your bestfriend after experimenting?

Sorry that this is a long description, but I tried and failed to keep it short; so here goes: I met my best friend in sixth grade. We grew close during junior high and then I moved. After moving, we wrote letters, sent texts, emailed, and talked on the phone every night until we fell asleep. We kept in constant contact. We spent every summer together 24/7. Right after sophomore year ended, I moved back. We cuddled and laid together for hours during the night, just talking and holding onto each other. She had had back surgery during junior high, so I felt very protective over her. She seemed to like that a lot. We had this little semi-intimate thing that we did where she would lean in and touch my nose with hers. We did this a lot. Several times, though, one of us would lean too far (I blame it on the dark, but I feel like it was on purpose) and we would brush lips. I always kind of shrugged it off and laughed and she would, too. But, one night she leaned to far and didn't pull away. I was laying there and I couldn't exactly jerk back, and most of me didn't want to. She asked the question quietly, and I kissed her... We grew close, so close. We could finish each other's sentences and we never left each other's side. I had never trusted or felt so strongly towards anyone before, and she admitted the same. Our experimenting progressed and, well, there wasn't a part of each other that was hidden anymore. We accepted each other and I feel like it was probably a lot more than a friendship at that point. But she became scared of getting caught and i was too. She eventually ended it after junior year, telling me that she didn't want to. But, she is still my best friend. I swallowed my broken pride and heart and feelings so that we could still be best friends. It is now the end of senior year. We are already signed to be room mates together at college and we have every class together. We even work at the same place. I still have feelings for her. Our friendship suffers, though. We fight a lot and hurt each other more than I could have ever imagined. It's hard to be around her when I'm so broken inside and I don't know if this is normal. She's my best friend and I would rather keep my heart break than lose her. But is this normal? And what can I do???