You are experiencing things lots of people get with PMS which comes before your period (pre menstrual syndrome). You had protected sex. That isn't 100 percent safe but you didn't have a broke condom, so there is no reason to think you weren't protected. Women do not get symptoms of pregnancy immediately by the way. So, relax. And sex is a big deal. If you are anxious, my suggestion is to not have sex for a while. good luck