UTI ?!?

I've had a UTI once every year for the past 3 years since I've been sexually active. As advised I pee after sex every time and wipe from front to back. Yesterday the symptoms came back at about 3 in the morning and I couldn't go back to sleep after it because of the discomfort and feeling to pee again. At the moment I can't sleep at all because the feeling is unbearable and the only thing that comforts me is sitting on the toilet!!! To make matters worse I'm currently on my period so I can't exactly have any tests taken.. What do I do?