Late period

Brianna

So I couldn’t get a refill on my birth control for a month and within that month me and my bf did have sex but he didn’t cum in me,I was supposed to start my period three days ago but I still haven’t. About five days ago is when I got a refill finally and the test was negative at the doctor. So my question is could I not be having my period because of missing a month of the pill after taking it constantly for over a year or should I be worried?