Very likely it is a urinary tract infection
. Drink plenty! plenty! plenty! of water. Unsweetened cranberry juice found at the healthfood store. Blueberries too. See your Dr asap. Macrobid
works well and fast!
Usually during sex bacteria like ecoli gets into the urethra
and can be quickly washed out when you urinate immediately after sex. If you fall asleep and forget to pee it gives the bacteria a chance to create an infection.
Do not have sex until this is taken care of and from now on go pee immediately afterwards! That advice comes from lots of UTI experience.