so at the end of may, i had sex with my boyfriend for the first time (we’re not virgins) and it was at the end of my period. fine. every period since then has been coming earlier and earlier. last month it was like 5 days early. but today i just got my period and it was 8 days early. it used to not do this until i got with him. also in january i had knee surgery and after the surgery my period was acting weird as well like i think it came a week or two late. could it just be going back to normal?