Hi, i had protected sex with my boyfriend (5th august) and he did not ejaculate inside of the condom. my period came 5 days later (10th august). my next period was due on the 6th of september but is a week late. i've had slightly sore breasts and i've gained 2 kg. i took a pregnancy test 4 days into my missed period and it came out negative. could i still be pregnant ?