Please help feel very confused and distressed reassurance please?

I really don't know what to do I've loved women for as long as I can remember and have only ever dated women I'm 16 years old and feel distressed feeling the way I do... I keep getting these intrusive gay thoughts driving me insane and I really hate it I really really do not want to be gay nothing against them or anything I just I want a wife kids and a family... I'm still very attracted to women etc... But why has this suddenly cropped up it's been going on for maybe 2 months now and I don't know what to do I remember my exams were just starting when I began to feel this way... Has the exam stress made me feel sexually confused? I would never experiment with a guy... Only women I planned to have sex with a girl earlier but couldn't as her mum was there I felt excited when I was with her but I don't know how to drown out these horrible thoughts all I want is my life back. I've only ever watches straight porn and still continue to now so there are signs I still love women... And say if I get on a bus I'll only ever look for attractive women etc... I just can't understand the cause of why this has happened I'm an attractive guy without being arrogant so I can get girls but why has this happened? Is there a therapy I can have that can get me back? Please can I have some reassurance that this is normal ? I just want to get back to me :( but no stupid answers please as this is very distressing thanks... X