Is it normal i cant get it up cause my brain?

Cant really wrap my head around it but for some reason i cant get it up when I'm with women. I do not have a problem getting to that point, but it seems my thoughts are distracting me to the point where i cant perform and its really depressing. I'm not gay that's for sure and i don't want women or people in general to think that. I haven't really had a great sex life but I fiend for it. Now when I'm in that position all i can think about is getting hard and failure is right around the corner. Really stressed and afraid to talk to chicks cause i feel like no matter what i do i am not gonna get it up :S