Should I be worried?

I am on birth control. It has been very consistent for a year now. I kinda messed up this recent pack on spring break, I took every pill but they were at max three hours late (one day). I started my sugar pills Sunday, and I normally start my period Monday but I still haven’t gotten it. I had protected and unprotected sex Sunday, but he pulled out way before we finished to put a condom on. I’m having really bad cramps, but nothing else. I had a little brown spotting Tuesday and Wednesday but now it’s just really bad cramps. I am going to buy a test soon, but I just wanted someone else’s opinion to ease my mind a little I guess.