Scared

Hi, I need some advice.So at the beginning of November me and my boyfriend had sex, he wore a condom and I'm on birth control but it's a medium dose. All this week I've been experiencing really terrible pain like cramps but more upwards. I haven't started my period, I should start this week or next but I'm super paranoid. I'm on birth control because of the pain I suffer from every month, cramps have fucked up my back greatly. I'm worried for the worst, I really can't afford to be pregnant, I really can't afford to have a UTI caused by sec tho when I pee it doesn't hurt and it's not brown. idk what to do, I woke up this morning because of pain and I'm just worried something is wrong.please help!