Sick to my stomach day after sex

As the title suggests, I had sex yesterday, and basically all this week, and I woke up with an upset stomach. We use condoms but I am not on birth control currently. I has to order my diaphragm. My urine is a little dark but I am not sure if that is a factor. I just am scared I am pregnant. I should also mention I have irritable bowel but am not sure if that is a factor either.