If you ovulated on CD17, then you will probably have a 31-32 day cycle because your leutal phase is still usually always 2 wks long (the time from ovulation to the day you get your AF) but some women do have shorter or longer leutal phases too. A shorter LP isn't ideal as the egg doesn't have enough time to implant properly is my understanding of it. It coul take a little while for you to get back to a cycle that is regular for you kwim? If you aren't successful this month, track your cycle a bit more closely and see if you can pick up any regularity to things that happen over the month. You could try using Fertilty friend and see if it helps. Good luck