??? Idk

So I had unprotected sex Aug 30-sept 5th. I got my period sept 12-16 all my period apps are saying I was supposed to start my period on the 2nd. So I’m about 6 - 8 days late I believe. The only thing I have noticed us my boobs feel so big and full. Even my bf noticed it. I bought a pregnancy test and smh one was digital and once I opened the package it started as if it was already testing but I didn’t even pee on it and came out negative. The other was regular red dye And I was able to see a little line but I’m thinking it was an indent. Is it possible I’m pregnant? I hate wasting money on pregnancy tests only to end up seeing I’m not :( I’m probably going to buy another even tho the chances of me being pregnant are not it. I’m just confused as to why my boobs feel so big. ( i hv small ones so you can definitely tell when they’re big lol )