Nauseous like crazy

I’m waiting on the office to call back for an appointment so I wanna ask you ladies as well if you’ve experienced this. I had a period almost a week ago, very short & very light(had this happen before but it’s been a LONG time) but since then I’ve been extremely nauseous and tired and it just hits at random times. I took a pregnancy test Sunday afternoon and it was negative, I also took one before my “period” it was negative as well so I’m sure I’m not but is it possible to be pregnant still and it just didn’t pick it up on either test? Or have you ladies experienced this and it been something else?