Irregular periods and smaller uterus.

Hi, I'm having irregular periods from the starting days. It comes once in 4-6 months and sometimes only after taking pills. I tried taking the 21 days tablet for 6 months (based on a doctor's advice) and during that period the cycle was regular. Last when. I took USG the results said that I have a little smaller uterus than the usual size. I'm very much worried about myself as I'm getting married by this year. I read that the chances of getting pregnant is less for people with small uterus. Is that true? What's the chance of getting pregnant? Is there any treatment for  that? I also have pcod ( based on a scan result which was taken 3 years ago) will that be reason for smaller uterus? What should I do to get pregnant without any delay? Please provide me a clear picture of my problem as every time I see doctor i get different opinions and what's the best solution for my problem?