Suspected UTI

I think I have cystitis, a bladder infection. I can only put it down to not having a wee after sex. Can anyone let me know if it is, I can't find the time for a doctors trip right now! I've read online it will sort itself after about a week. I have pain at the end of weeing, abdominal pain (take me ages to get comfortable and fall asleep), and external vaginal pain on and off, I also feel the need to wee more often than usual.