Brown Spotting for 3 days

Hey ladies! I got off birth control in november, had a miscarriage February 18th, and have had one very normal period since then. It's been around 43 days since (which isn't surprising since it took a while for my last one to start). I have had brown spotting when I wipe (and varying but small amounts on a panty liner) for the past three days. I've never experienced brown like this preceding my period, only at the very end when it's lightening up. Should I be concerned? I thought I could be pregnant and this be implantation bleeding, but if it's not I'm wondering where my actual af with real blood is...I might be over thinking but any input would be greatly appreciated!