Could I be pregnant this early?

Hi all! I just started using preseed this past Friday..we have used it twice since then and are planning to use the rest while I am ovulating in a few days. The past few days, literally since Sunday I have felt different. My stomach is achey, kinda like its being stretched and pulled. My ribs are also sore along with my breast, but not too severe. I also have moments where I think I'm nauseous but then it goes away. I also am up all night restless and sleeping in during the day since I am off for the summer. Is this just my mind playing tricks or could I be pregnant?