Regular cycles but luck ttc

I been with my boyfriend for almost 5 years and never really had any type of birth control and have only gotten pregnant once last year but unfortunately end in a mc at 6weeks. We never really been ttc we wanted it to happen naturally unexpected but that's just not happening I been tracking my period and cycles for about an year. my cycles got a little all over the place for a while before the mc happened but after it they got back to normal and are exactly 32day cycles and period lengths of 6 days i dont bleed between periods have only missed my period 2 times ever and that was about 2 years ago I don't drink, smoke, or do any type of drugs what could the problem be why am I not getting pregnant I been to the obgyn but has never told me anything about a problem that she has seen or been alerted by I even drank one prenatals for a while but still no luck anyone going through the same thing as me or any suggestions on what I could do?? What should I ask my OB gyn to check or what exams should I request to me tested on