Implantation Bleeding? !?!?

So, I had what I felt like or thought was my period on the 16. Which was the day I was supposed to get it. But it went off on on the 19 which is not normal. I took some test but they came BFN. But here it in the 27th and I'm spotting which is way to soon for my period. Me and my husband had sex on the 20th, 22nd, and 26th. I'm thinking it's way to soon for implantation but I'm unsure. What do you all think?