How can you not be fertile after having a miscarriage.i thought that infertility is when u can't or never been pregnant?

Yes: You can have fertility issues after a miscarriage. Infertility can be acquired after fertility for a number of reasons. I would follow closely with a ob/gyn and they can help you through this.

Fertility/Miscarrage: Most women have a successful pg after miscarriage (75%). The risk of miscarriage is higher (25-30% from 15%). About 1/500 couples have recurrent losses (rpl), which we consider to be a form of infertility as the couple may not have any live-born children. Tests are different for rpl and about 50% have all tests normal. Some rpl patients later cannot get pregnant too. See doc for full discussion.