My period is a crazy bitch

Bella

My husband and I have be very well sexually active. We don’t use any type of protection. However, I have yet not gotten pregnant. Now what throws me off the bus is the fact that my period will be late a week or two maybe even more, and yet not pregnancy. I have no idea why I’ve been late so much and it’s irritating the bananas out of me. I literally need help understanding the women body.