TTC for second.

Hello all-

I have a 2.5 year old little girl. With my daughter I was off birth control for only 3 weeks and we had sex once and BOOM! I was pregnant with her. 

I have been off birth control since July 2016 and we started trying for our second child in August and no luck. I am so upset and just starting to get scared. It was so easy the first time. I am starting to see my cycle is very irregular and I am sometimes on a 30-34 day cycle, it's wild how irregular I am. It's so frustrating considering how easy it was for my daughter. 

I've been using these ovulation kits and no luck. Maybe I just don't understand the ovulation kits enough. I know I'm ovulating because I get painful cramps from it. I feel the cramps on both sides and when I'm done no more pain. For example, I got my period Nov 23-27 and I am still waiting to get my next period and according to the test kit I was ovulating on Dec 10 and we were intimate that night and I am not pregnant. So maybe I am just not following the kit right? I did go to my Gyno and She assured I was fine and have tons of healthy eggs in there. Any advice or help would be appreciated. Thank you all.