Am I bisexual or?...

So whenever I masturbate I watch lesbian porn. For some reason porn with a guy and a girl just doesn't do anything for me. Only watching lesbian porn or fantasizing about being with a woman turns me on when I am masturbating. However when I am done masturbating I get weirded out by the porn I was just watching. I have thought about it and I am 99% sure I could never actually be with a woman in bed. The thought of eating a woman out grosses me out. I am never attracted to other women either only men. Is this normal for being straight?