here is a caption explains better.
Can I have a period and still not have ovulated?
Having a period does not necessarily mean that ovulation has taken place. Some women may have what is called an anovulatory cycle, (meaning no ovulation) and can experience some bleeding which is mistaken for a period, but it is actually not a true period. This bleeding is caused by either a buildup in the uterine lining that can no longer sustain itself or by an estrogen level drop. The main way to decipher if ovulation is in fact taking place is by tracking the body temperature.
Not stupid at all.normally true periods occur anything up to 16 days past ovulation,this is when the linning sheds due to none fertilization.so answer is no,what you will get is breakthrough bleeding.isnt a proper period.sounds like somtimes you do ovulate.other months later than normal.however with this can make timing for sex in order to concieve more difficult.it maybe worth discussing with your doctor other options,they can put you on birth control for few months,this is said to help regulate your cycle.