Periods and sex

So my periods are not usually normal but they always seems to get extra crazy when it comes to not having sex for a while I can always count my period to start on the same day it just depends on how heavy it will be and how long it lasts but when I am sexually active it always seems to through my period off. It always comes late or early but I always have symptoms. I’m currently 2 days late and experiencing no symptoms. I have no idea what is going on can anyone help me out? And is anyone in the same boat?