In very small percentage of women, the COCPs can affect follicle development, as these drugs act by suppressing the hormones required to stimulate the follicle growth. The treatment you are getting is accepted method to treat such a problem. However, you may have had this problem before starting the COCPs too; and this has been unmasked now. Whatever cause, for ovulation induction, there are many drugs and many protocols.
These drugs and protocols have to be adjusted and selected upon the individual case.
A pelvic (internal )examination by a gynaecologist and a hysteroscopy and laparoscopy will tell you whether or not your reproductive anatomy is normal.
A very small uterus can lead to problems like abortion or preterm labour. However, not all pregnancies in such women end this way. So no point worrying, as you cannot change the size of your uterus!