Implantation Bleeding?

I NEED HELP! So, my husband and I decided to start trying for a baby.. i literally have only been off my birth control a month, we had sex pretty much every day during my ovulation window. I'm now having some light bleeding or "spotting" during the time which should be my period. My periods are usually fairly heavy even on the pill so I was expecting it to be heavier than usual. I thought this was maybe implantation bleeding? Has anyone had any experience with this? I took multiple tests throughout the last couple of weeks and they all say negative but, I'm wondering if I took them too early? Thoughts??