UTI even after I peed after sex??? HELP!!!!!

Hey! I'm freaking out!!!!! 2 days ago I had sex with my bf and I peed right after like usual. This morning I woke up with a UTI.... Why?!?!?!?!?!? 
I specifically peed after sex to avoid this issue!! 😭😭😭 it burns so much and I'm even supposed to get my period today!