Is it normal to wish your friend was single?

I have a friend who I've known for a year and a half. We are both bi sexual females, and she has a girlfriend. In the past few months or so our friendship has gotten so much closer and better than ever. I never really knew how much of a cool chick she is until we started hanging out so much. I also can't believe how beautiful she is to me now. Not that I didn't think she was before, but it's like now when she smiles at me its like a million shooting stars are making a fireworks display. Yes, I know that sounds corny but its how I feel :p Since we've been hanging out, I've grown feelings for her and they keep getting stronger. Every time I see her I feel like I've just won the lottery. And sometimes when I can't see her I feel really sad and miss her so much, then I find myself dying to see her again. The thing is, her girlfriend lives overseas, and she's coming over this week. She's really happy and I'm happy for her, but it hurts. It hurts to know that she's going to be in a little world of love wih her girl in a few days, and I have to sit there and watch like its not going to affect me at all. I have to be happy for her though, because her happiness is whats important, and I will be, but its hard. I wish she was single so she could be with me, but I feel cruel because I should be worrying more about her happiness. Not that I know I'd have a chance with her anyway, but yeah. Is this normal?