What Causes Breast Tenderness And Frequent Urination While Being Sexually Active?

I m wondering if I m pregnant. I had sex with my boyfriend on June 26th, 3 days before my period was supposed to start (I just use a calculator to track it, and I am very regular, 26-28 months each cycle). 5 days after the 26th, my period started (I think). It lasted 3 days which is normal for me and I used tampons all day and night, filling all of them. I had cramps and cravings as well. I thought everything must be fine and that I wasn t pregnant but now I vebeen feeling very tired and I swear my areoles are bigger. My breasts are slightly tender but no more than is normal a few weeks before my next period. I ve been peeing a bit more (but just 1 or two times more a day than normal and I ve been drinking a lot of caffeine.) I randomly feel sick, but not like I m going to throw up... Just kind of off. I mean, I know that I probably am not pregnant but I just want to ask and get more information on whether it s even possible! (Mostly to hopefully ease my mind.) based on all of this, could I be pregnant?? I ve also been having mood swings (one moment happy and laughing and the next so so annoyed at the tiniest things!) PLEASE HELP.