It cant be another UTI… not again

Patient: I am 18 years and 10 months. I lost my virginity almost 3 months ago to my current boyfriend. As expected it was very sore the first few times but then it got better. However I got what was suspected to be cystitis the first time and so was prescribed antibiotics. At that time I started on the pill, Microgynon. Not long after the intense pain was back. This pain included always feeling the urge to urinate, little amounts of fluid coming out and concentrated urine, even when I drank plenty of water. Again, back to the doctors, more antibiotics. The third time she took a sample and sent it off to the lab… no concerns. I’m now experiencing this for the fourth time and I cant help thinking its to do with sex. My boyfriend is clean and was also a virgin so we sometimes dont use a condom. We use extra lube when needed (which is quite a lot). He is circumcised. Thats all the relevant information I can think of. Please help me!