I has 10 days ago. We used the condom, but I think it might have slipped a little. Could I be pregnant?

I ended my period a week before we had . I was not on birth control, and we had pretty rough , three times that night. He used a condom but I think it slipped a little when there was some pre *** in it and he took it off and put another one on. He said that it didnt slip and he didnt worry about it at all, but im still not sure.. About three days ago, I started having a lot of gas and pains. Not extremely painfull but I don't get that much gas very often. and I'm having some pretty bad stomach cramps and sharp pains. A little nausea but barely. Are these pregnancy signs? Can I notice signs this early? When can I take a test and find out? What's the chances of me being pregnant?