Unsure

I've just spent almost an hour reading through this forum about how other people are unsure of their sexuality. I decided I needed to ask help for myself.

I'm a 20 year old female and have always questioned my sexuality but just thought that was because I tend to over think everything. I've had two serious relationships with guys, both lasted 2 and a half years. Obviously I'm only 20 so I had these relationships quite young, they took up ages 13-19. I always thought I had to depend on a male. I've now been single for over a year and it has been very weird. I find guys very attractive, a certain type though. I like fit men, with muscles and nice smiles. I have slept with a lot of guys since being single but the weird thing is, it has only ever been when I'm drunk. I can't remember the last time I slept with a man sober. When I was with my ex, and ex before him (however this could have just been an age thing) sex didn't mean much to me. They'd always try but I was just never in the mood for it. At the end of both relationships I found myself feeling sick just kissing them. I've always been attracted to girls, when I was younger I forced myself to ignore it. As I got older I thought I was just appreciating beauty and there was nothing wrong with that. I've had guys try and get close to me, and I try to make something of it but I get to a certain point and I push them away because all of a sudden I'm just not interested and I don't know why because they are actually really great guys.
Now I'm so confused as I have been thinking about girls sexually and around certain ones I feel nervous and don't know how to act. I'd like to mention that I don't masterbate, I can't seem to do it, I've tried but it makes me feel uncomfortable and I don't know why. I've only ever kissed a girl drunk and it was a friend so it doesn't even really count. I don't know if I'm over thinking this but if someone could please help me understand why I'm feeling the way I am would it would be greatly appreciated.