Skipped placebo last month, now no period?

My boyfriend was going to be visiting me at college, and of course I was scheduled to get my period exactly when he came, so I skipped my placebo pills and started on a new pack immediately. However, I still ended up getting my period by the end of the weekend, so I figured it hadn't worked. Now, a month later, my period is late. Is this normal? Should I be worried?