I am sorry that af started for you today... I hope that you have a better chance of conceiving in the following months... with that many mature follies or immature follies it kinda sounds like you have a case of PCOS... I would definitely follow up with your doctor to see what they can do for you. Best of luck :)
You only ovulate once in a cycle somtimes our bodys fail to ovulate first time.so will try again,this may be what happen to you,release of more than one egg does happen but within same time frame resulting in possible twins if conception occured.i would say you ovulated later,as 20dpo is bit long not to have a period.i would wait few more days,and test,or maybe ask for a blood test.