Spotting?

I had a miscarriage in August, and my period for September was completely normal... we’ve been trying since our DR gave us the green light. I made sure to use the ovulation strips for peak days and do the deed on good days. I was due to start my period last weekend and I started to spot and thought okay this is it.. I’ve been LIGHTLY spotting for the last 4 days and it has not gone up in flow. It seems like it’s tapering off today. I took a pregnancy test and it came out negative 🤔. Could this be implantation bleeding? Or are my periods mostly out of wack due to MC?