Pregnancy scare help

Hi im on birth control so i dont get my period ever and i had unprotected sex about 5 weeks ago. my boobs have been super sore for the past 2 weeks but i have no other symptoms. i took a pregnancy test 2 weeks after having sex and it was negative. i took another one this morning and it was negative and then i saw a faint line after 20 mins. could i be pregnant ??? pls help im v scared lol