Hi,
Im a girl and Im currently going through this problem and let me tell you, everytime I look at a girl I panic and think 'oh there pretty' 'oh there cute'. I guess it is normal and yeah hocd changes everything you thought you were straight your entire life? boom hocd tells you, you were gay your entire life and you start believing it. Try to get a hocd therapist to help you get over this nightmare
Good luck :)
Of course...that is how OCD tormets us. Our mind turns against us. We say black and our mind says white. It is like a constant battle with your ownself. What you need to learn is to let the thought go. Let is wash over you and say "whatever" because when you do that you take the fear out of the thought. It is the fear that keeps you in the OCD loop. You are stuck right now and you are without the means to help yourself. Your best bet is a psychologist that teaches cognitive behavioral therapy.