Irregular Periods & TTC

A bit of a back story..

I got pregnant in 2012 and it literally only took my husband and I about a month of trying. Up until that point in my life I had always had regular periods. After having my baby via c-section, my periods became extremely irregular. I bled for a rather long time after having him (I saw my OB, they ran testing and said everything was fine and it would work itself out). After the bleeding stopped, I didn’t have a period for a few months and now only get them sporadically. It can go anywhere from 3-5 months apart. We haven’t used any contraceptive and I haven’t gotten pregnant in the last 5 years, not that we were actively trying. But now that our LO is 5, we would like to start trying again. I know that I need to go seen a doctor, I’m just really worried and scared that I have something really wrong with me. So my question is has anybody had extremely sporadic periods such as mine after having a baby and if so, have you found out why they are? Has anybody been able to conceive with such irregular periods? Sorry it’s kind of long, but I just wanted some advice or other peoples stories while I find a new doctor and wait to get seen. Thanks in advance!