My regular cycle is 36.my last period changed to 33.my last period is march 29,and had sex april 15.does the changed cycle and sex just made it late?

Cycles: Sex does not alter the menstrual cycle unless you got pregnant. A 3 day variation in cycle length is not very abnormal. Most people have a few days of variation from time to time. If you think you might be pregnant check then check a home pregnancy test. If you are not wanting to be pregnant consider starting birth control to prevent and help with cycle regulation