Irregular and TTC

Kayleigh
My husband and I started TTC in August. We got married last year (most stressful time ever) and my periods were completely regular. I've been off of birth control for just over a year and a half. The only irregular period I had was the first one after stopping BC and it's been regular ever since! 
Since we've started TTC, my periods have been weird. I was just under two weeks late after the first month and it finally came but we missed our opportunity in September because of it. Then in October it came 6 days early, and now I'm 4 days early. What is happening?!
Anyone else able to relate?