I fantasized over my friend and then rejected her
I cannot understand why you would do this. Tell me what happened when you rejected her.
She was in tears after hearing my feelings. I needed to move on.
Using your friend as fodder for your own personal fantasies is incorrect. When someone finds out about your feelings and you subsequently reject them it causes them confusion and pain.
I think she's a slut.
You should not call people names and treat them so poorly because you want to have a fantasy. It is important to see others with respect.