Prego? please help me?

So here is the situation. My girlfriend was due to hit her period today. She usually doesnt work like clockwork and it can vary a day or two in either direction. However this particular time, her are sore like they usually are this time. And she is pretty hot to the touch. However, she said that she feels a little more sick to her stomach right now on top of the usual cramps that she gets when her time is suppose to hit. Now as far as could she be prego....we always wear a condom but this last month there was one time where I was in her for like a minute without one....which I know is a no no. So I dont want to be thinking to much into this and freaking myself out but I just needs some opinions cuz Im not a woman. so to recap.....day late, tender s, a little hot, emotional, feeling ill. PLEASE HELP