I think I'm in love with my best friend?

I've never really thought about myself as a before but I'm definitley attracted to my female friend. We do have a close relationship, we both love each other alot, but have never kissed as we have done with other friends, We even talked about this once, us both saying that for the amount of time we've known each other it's strange that we haven't.. neither of us really said why but I was thinking that it's because I'm so deeply in love with her and if i kissed her it would have to mean more than just fun, like i can't go there without it showing her how i truely feel. Also the thought of her being with her boyfriend sort of tears me up inside... i've had boyfriends but never felt this way about any of them. I want to tell her, not just to be honest but in case she does feel the same way and has been putting on a front with the whole boyfriend thing, she has got quite an idealistic view of relationships and i think maybe just wants to be 'norma'l in comparison to the quite dysfunctional background she's had. What should i do?