i had unprotected sex with my bf 4 weeks ago. 1 week after having intercourse i had what looked like my period but very lightpink & no clots. i had somewhat abdominal pain with increased fatigue and headaches. i took a pregnancy a week later and it was negative. now i am very gassy and moody. should i take another pregnancy test?? i also liked to mention that ive been loosing some weight. could that be the cause?