nexplanon period?

I had nexplanon put in about 3-4 weeks ago (newer form of implanon) and started spotting lightly brown blood. Today there is a little more. I'm not used to that since with my normal period I don't spot, I wake up in the morning and my period hits HEAVY. so my question is what were other peoples experiences with periods while on this BC. I'm not sure what to expect with mine. I was told there was heavy bleeding, but I don't seem to have that. Yet. Lol. Anyone else spot lightly and then did it get real heavy?