No, it's not the most bizarre thing I ever heard, by a long shot. It sounds like you were a very self-involved young man, narcissistic and anxious about succeeding at college. So, yes, it was mostly your fault. She may very well have been interested back then, but few women will put up with such rejection and not lose their positive feelings. Now you are left with the "love that never was" which can be a very potent fantasy. Since you made most of it up in fantasy, based on a few ambiguous clues, you never had to deal with her as a real, human, and therefore probably disappointing person. Part of the difference between romance and real love is going through that period where we break through our romantic fog and begin to see the other person as they really are, and we ourselves are revealed to be a fallible human, also.
You never got past the fantasy stage with her, so she seems more wonderful than any real-life woman. I think you need to mourn the loss of this impossible dream, so you can move on to a real-life relationship. Try using the exercise "How to Write a Love Letter" at my website, which will help you release your feelings and move on. Then read the article "Surviving Loss and Thriving Again," which will help you understand your grief. When you've done that, there are many morearticles about finding a relationship that will work. The Unofficial Guide to Dating Again will help you move forward.