Obsession or what?

So, after more than year and a half ago i was with this girl (first and last(to this point)). We were together for like a little over a week, but the whole wooing process and the aftermath along with the relationship lasted for about 3 months. Anyway, bottom line is that she had left a huge impact on my life/mind. I was amazed at how relatively easily did i got over her breaking up with me (at least easier than i thought). But the ting is that during the course of this time that has passed in between i didn't spent much time thinking about her, but after a year i started dreaming her very often. Last night even i dreamed about meeting her on top of a fortress/park and that she was sobbing and was angry at me for something and after that we started to make peace and to walk along the walls. Every time i dream of her i wake up sad as a motherless seal, that's very sad, after realizing it was a dream. It's also important that we do not talk ever since we broke up, no particular reason actually, we were just both way too much strong-headed to step back....So what should i do? :/