Period cramping or implantation cramping?

Hi guys! I started experiencing cramps this morning and I was wondering what exactly it is from. My period is exactly in seven days, but I usually don’t get it because I’m on birth control (mini-pill). I took my pill a little 20 mins late last week and then I had sex the next day (he did not finish im me) and pulled out. I have been on the pill for four months now. What do you think this is?