Ovulation period, had unprotected sex. Light bleeding, constipated, bloated, headaches, back pain. Pregnant?

I had unprotected sex 4 weeks ago in my window of ovulation , abt a week later I started having cramping and felt off, my period never came however 4 days after it should have come I had light bleeding/ spotting which was a brown colour mainly when wiping, however I used a panty liner. Usually my period is quite heavy the first day and I need to use tampons. Since then I ve been quite constipated, bloated have loss of appetite some headaches and can t seem to sleep even when tired. I have some cramping in my abdomen and some lower back pain and my skin has become dry. I did a home pregnancy test 1 day before my spotting/ light period which was negative could I be pregnant