Very irregular

Tiffany • Been married since Sept. 2010 and have a beautiful little girl that was born via c-section Dec. 2011. Trying for #2!
I don't think I have EVER had a regular, every month, so many days period! My DH and I are trying for our second child. When I became pregnant with my daughter we weren't really trying for a baby so when we stopped using protection it took six months to become pregnant. Now that we are trying I've been trying to track when I ovulate but how can I do that if my last period I had was in March of this year?! I went in July to get my Pap smear done and the doc just gave me pills to take for 10 days to start a period. I had a period for almost 2weeks! The longest I have gone in the past without having a period was 7 months so I'm really use to not having it. And now that we are trying and wanting to get like yesterday it's really frustrating. Does any one have any advise or similar problems?