Period lasted a day 1/2 (is this normal?)

Monica

My period usually last between 5-7 days. I started it yesterday morning but I noticed that my blood was a very dark brown.. had maybe a half full pad in the whole day. Today I had maybe a few drops and it was dark brown just as it was yesterday. I thought maybe it was implantation blood but at this point I have no idea..... Not even sure this was a period..