quick question please help!!!

hi so i had unprotected sex on april 6th but i am on the pill. i’m not very good at taking it so i was kind of worried. anyway, i got my period on april 18th and it was about 5 days of normal bleeding. i also took a pregnancy test 22 days after that was negative. i thought i was in the clear, however this week i’ve been peeing so much, have lower back pain, headaches, and a huge increase in appetite. i’m supposed to get my period again in a week so it could be from that but it just seems a little odd. if anyone has any information please feel free to share it!