Hi! I have this problem. We tried to conceive for a year or so, but nothing happened. I asked the Dr for advice, they referred me to the hospital. The hospital arranged for an 10 minute operation called a laparoscopy, which is basically a camera through the belly button to see what problems I had, if any!
The result came back as basically I don't ovulate. I kind of new this was going to be the case because I have my periods twice a month.
Anyhow, I was put on some tablets for a few days at the start of the monthly cycle. The tablets were called clomid or clomiphene (I think thats how you spell it). This is how I conceived my daughter. The hospital said that there was a chance after having my daughter, that everything would return to normal. Sadly it didn't, and they said that if I wanted to conceive again, I would have to take the tablets. I was happy with this. However, I fell pregnant naturally, don't quite now how.
Since the birth of my son, my period problems returned (twice a month), which I do detest. Have been thinking about a hysterectomy in a few years.
Please don't worry about it, the fact that you have conceived a child indicates that everything is working. You should visit your Dr and discuss your worries.