Gay guy having feelings for my straight girl friend?

Alright, lately I have been innocently lying in bed with my best friend who is a girl. We're extremely close and I love her. We hang out every weekend and normally end up asleep and cuddling. Well she has a boyfriend and she loves him, I think, and at the moment I don't have anyone. Well lately when I'm lying there with her I start to feel closer to her in a not so platonic way. I just feel like I love her more than just to be best friends. She has also said before that she wishes we could just date because we get along so well. 4 years no fights. Anyway I don't know what I should be doing? please any feedback would be great.