Haven't had a period in over a month

Christa
I got off of the pill abou 2-3 months ago because I never got a call for my next appointment to get more. I wasn't too worried about it because in my current relationship, we've promised to not have sex until marriage. I've had one period since I got off of the pill and it was about a week late. But other than that, I haven't gotten a period. Any advice? Should I be concerned? Should I go back on the pill?