i have a 20day cycle and was getting really frustrated because i thought this was too short to conceive. I eventually booked in with doctor who sent me to get my bloods done and also referred me to infertility clinic because of my age and we didn't want to waste anymore time.
So i got bloods done on cd17. Results came back everything ok except they showed i hadn't ovulated. I got upset at this but the nurse said we will do them again as we might have done it too late in cycle so on next cycle went back on cd11. Meanwhile appointment came in for infertility clinic.
I never got results back from that test as i got my bfp on cd 21. I think i was ovulating really early maybe as soon as my af finished and thats why i was missing it.
So, i would maybe go to doctors and get bloods and make sure that you are ovulating and try and find out whereabouts you are ovulating in your cycle. Hope this helps you x