Implantation bleeding or early period?

Hello, my husband and I are trying for baby #1. I started bleeding one week before my period was due. It started dark red and had clots, this was quite heavy. That lasted for 2 days and gradually slowed. Then I had a light red color on the tissue after using the bathroom, which lasted 1 day. Then a brown discharge for 2 days. I didn't experience any cramping or pain, but I did have a headache, fatigue, sore throat, hot flashes, and leg cramps. I tested 3 days before my period due date and day it was due, both negative. My period has been regular for years and this is the first time it came early. Has anyone had similar experiences and a positive pregnancy? Thanks!