Absolutely frustrated

I just need some sort of opinion.. 
I was on BC for about 3 months. I was terrible at remembering to take it. The last month (november) I took maybe 6 out of the whole month
Got my period on Christmas my next period showed up on the 18th of Jan. We of course trying for a baby the fertile week (Jan 3-8) but then I got my period! Now I'm three days late, haven't had sex since then I've been out of state with family. 
My period was due the 11th. Could it possibly be irregular cycle due to the pill even though I was on it at max 2 months... (October being the last month I took it religiously) 
I guess what I'm getting at is I got my period two weeks after trying for a baby... Is that normal. Could I have been pregnant and still got that period(which was very unlike any period I've ever gotten before)  ugh just frustrated