Sexually confused please help?

I've been straight all my life for as long as I can remember why have I suddenly became confused of my sexuality and how can I get back to normal. The way I was 2 months ago...? I remember the time this came on was when my exams were literally starting a few days later I'm 16 years old and have dated women all my life and plan to stay that way but why has this cropped up ? Why can't I get my life back on track... Is there a form of therapy I can undergo that will get me back to normal? Why am I getting these intrusive gay thoughts as well? I loved my life b4 and hate it now and just want to enjoy my life the way it was 2 months ago as a straight teenager? Nothing against gay people but I really want to be straight with a wife and kids :) please help and give me reassurance that this is normal and I can overcome it regards x