pregnancy sympoms and birth control.help

okk so I have regularly been taking birth control for almost 2 years. I was in Mexico for vacation from December 22- Jan6 and while I was in Mexico I finished my pack of pills and had my period.(this was toward the end of my trip) I was not home to be able to get my new pack so I was off from the BC pill for about a week. right when I got back on the 6th I got my pills and started to take them immediately. that same day I went over to my boyfriend's house and we had unprotected sex but he never came in me. on that same day and the following days I've been nauseous and now my nipples are sensitive but not crazy sensitive. I'm now worried that I could be pregnant ,so my anxiety is through the roof and I'm not sure if that's what causing my nauseousness??

or the fact that I was off the pill and went back on a week later and these are just symptoms of the pill??I'm trying to callm myself down and tell myself that I'm not because I had just finished my period a few days before we had sex on the 6th so I wasn't ovulating.