Possibly pregnant?

I had sex with my husband about 4-5 days ago. Well when we were having sex he needed to orgasm but I wouldn't let him pull out to go because I needed to so he said he was able to control it and hold it in(which I know people can do). Well he went outside obviously. Well two days later I was cramping and getting random waves of dull achy pain in my abdomen. I thought it was the food we had eaten the night before but I wasn't and still am not having diarrhea or vomiting. I then began to question my husband as to if he was 100% sure he went outside of me and didn't get even a little out on the inside. He says he is 100% sure. Well I wake up this morning and I'm EXTREMELY nauseous and dizzy. I think ok maybe I'm just dehydrated and need some water well so far water hasn't helped but idk. I'm not really sure if my husband can go inside me a little without knowing he did it can he? What do you guys think?