I went to the doctor, had an ultrasound on Day 21 of my cycle....thought it should be noted I have irregular period and 38 day cycles(ish). Anyways, my largest follicle was 8 mm. It was apparently supposed to be double to house a baby and become a corpus luteum. Could it have just been too early in my cycle? This is a new doctor I am seeing, and I don't go back until the 25th. I'm just wondering if anyone else has had this issue and what it meant for them. Apparently, the follicles weren't maturing.