Even though I did not end up pregnant, I am starting to think I am, now

Hello, I took Plan-B one step a few months ago , Aug 18, 21 hours after sex. I was having precautions over something. Even though I did not end up pregnant, I am starting to think I am, now. You see , after I took Plan B my cycles were shorter..I think they were about 21 days apart, around that number. I had sex 2 times, once when I was on my period last month, ( on my 2nd day) but it was protected sex, but he did rub himself on me but he did not go near the entrence and I constently went to wash myself, this was October 31-Nov.3rd. Then on Nov.15 I had sex again, protected but he did rub himself on me again but did not go near my entrence..I'm very scared I might be pregnant. He did not ejaculate in me in anyway or form, he always pulls out before he ejaculates (even with a condom on) and goes washes himself every single time he does ejaculate. I thought that my period would have came the 24th or 25th because that would have been 21 days since my last period <> I know that my cycle will change back to normal eventually it has been 3 periods if I count in my period that I got after I took Plan B so is my cycle changing back to normal now? I have not gotten my period..I've been having nausea today and a bit of stomach pain in my middle region and sometimes on my sides. I'm really scared that I may be pregnant..and do not know what to do..please can someone help me in what to do..?