HELP !!!!

Okay so me and my bf havent had unprotected sex since January, but ever since then i have been having symptoms of pregnancy. i have headaches , stomach aches , i be soooo tired even if i sleep 1 whole day , my breast have been hurting they've been tender , & its like this stomach pain that feels like a stabbing knife , i had two periods since we had sex , my first one was late , and it bleeded very lightly than usual but the one i recently had was supposed to come on friday & it did but it bleeded sooo lightly down there that it would literally take me up to days to fill a pad up (not saying i keep a pad on that long) but the next day i woke up on saturday i was still bleeding lightly then all of a sudden saturday night my period completely dissapears , and i have a period calculator that tells me when my period is supposed to come .. but on sunday & saturday night i been expiercincing little bits of blood down there , now on monday & today i've been seekng a brownish discharge , what does this mean?? i've tooken two pregnancy tests which both came out negative , my boyfriend also says that he didnt nut . im just so confused idk what to do