Pregnant?

Tve taken a hpt and it was negative which usually would set my mind at ease. Especially since AF seemed to come right on time. But I'm wondering if it's implantation bleeding. It's not like my normal period. It's much lighter. And I have almost ALL the symptoms of pregnancy. (Nausea, fatigue, tender breasts, mood swings, etc.) I've read that with implantation bleeding it usually comes when AF should and could come with the cramps but would not be as extreme as normal. I'm really just looking for some opinions on whether I should take a second hpt or go to the dr. Any help would be greatly appreciated :)