Getting over a girl.

If you were seeing her for 6 months you WERE in a relationship. However, either she changed her mind or she was telling you that you're perhaps more intro her than she was with you. That means, unfortunately, that's it. Either she was hurt in the past or just simply wants no commitments or ties

What you sound to be describing is your fixation or obsession. This may not be healthy. You're better off checking out and/or seeing others who will be interested in you equally. This one just won't work.

When she told you no...did she say not now - or maybe for some time in the future? If she just said no, then find someone else. This is what you'll learn from a little more experience. Are you in your teens, perhaps?

I agree that it is a form of obsession, but im determined to loose it, but don't know how.
She told me no, with the excuse that she broke up with her ex of 4-5 years a few month back. She texted me a month ago, and we texted back and forth the next couple of days.
Im 21 and I think that this might be the first time I really liked a girl.

Allow me to encourage you with pursuing a friendship there if she is willing. When I was 21 yrs of age, I can't say I was that different. The way to lose the obsession is keep finding, pursuing and exploring new interests - not just her or exclusively dating.

You're doing fine. If she still wants to get together now and then as friends...do so as long as you can keep a lid on the romantic fantasies. Clearly, she needs her space so let her have it. In the meanwhile, you'll be best to cultivate another relationship elsewhere if you are looking for romance.

Okay thanks.
Think im gonna spend more time loosing this obsession, before anything else. I don't think it is possible to be friends with her right now, as my feelings are still strong for her.