Late period after months without sex

Sirley

Is it normal for my cycle to become irregular after months of not having sex? I spent about 15 months abstaining from sex and when I finally did it again with someone it hurt almost as much at the beginning as when I lost my virginity and I spent a couple extra weeks without my period. I took pregnancy test and they al came back negative and my period is finally back. Can anyone please give me a bit of insight on this.