Well it Couldve Been Bad Timing...

As most of my posts on here say, I am bisexual (M). Or at least thats what I think, but maybe my body doesnt agree with that conclusion.So just last night I was chatting it up with my gal pal. We had decided to have sex because were good friends and have been horny as fuck lately. I havent had sex in three years. She had sex just the other day. So we park in a decent secluded spot, things get heated and she starts sucking me off. It was really good, and we were both really fucked up.Now, Im not sure what happened, but I got a wierd feeling in my stomach and realized that her sucking me off wasnt doing it for me. She stopped and asked what was wrong because I had, by that point, "deflated." I didnt wanna give any excuses, but ended up listing all of them.Now, Ive actually never gotten off when someone has given me a bj, even guys. But she asked me "is it because im a girl?" And the first thing I thought was, "uhm no. You are hot as fuck. Why would that be the issue?" But what if it was? For the last 3 years, Ive labeled myself as bi because I get turned on by both men and women, I think about men more often though.Was it timing? Do I just not get off from bjs? The make out sesh was awesome, and thinking about fucking her still turns me on, but what if im just kidding myself? Its not a crippling thought, but its enough to stop and think that maybe I dont have as much figured out as I once previously believed.Can anyone help me out here? Is there any experience you have that could help me understand why I has to endure such an embarrassing moment?