clomid only made one bearly matured follicle

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couple of months ago i had follicle scan on cd13 that showed a follicle that was only 13mm my doctor said it was to small for ovulation but the next day i got pos opk ? i remember calling my doc and telling him he told me it was impossible for ovulation? fast forward to this cycle i did my first round of 50mg of clomid and on cd 12 i had only follicles that was growing at 13mm went back in on cd14 and only one was still 13mm and the other grew to 16mm my <a href="https://glowing.com/glow-fertility-program">iui</a> was cancelled do you guys think i was not producing matured follicles could this be the reason im 4 year ttc and not getting pregnant? because clomid should of making my follicles bigger im thinking if they only grew that much on clomid what would they havs grown without🤔