Ovulation. Fertility.

I have a question. I've been told so many different things by others and by doctors. I just don't know for sure.

I had my right ovary removed, because of a tumor, in 2013. After my second son was born. 2 years later I had my third child.

Me and my boyfriend have been trying for 6 months to have another baby. And we haven't had any luck. Could it be because I only have one ovary? .. When it was removed I was told I would have no problems. And by a different doctor shortly after I was told your ovaries take turns each month releasing eggs. With one ovary it will only release eggs every other month. And then by someone else I was told that because I only have one it would do the work of both. Does anyone have any answers for me?