UTI issues

Sarah
I keep getting what I believe are UTI's. I wipe properly and go to the toilet straight after sex. I get them randomly, like not even near when I had sex or anything like that? They're incredibly irritating and wake me at all hours in the morning, I've told my mom a bit about it (I'm 17) and she wants to take me to the doctor but I don't want to answer any questions about sex (my mum is unaware that I'm active with my bf). Any ideas???