thoughts?!

I started what I think is my period 4 days early. It wasn't as heavy as my period, usually I fish out blood , but I only had a few drops on a pad. But the blood started off pinkish/brown to some reddish/pink and now it's gone. I would say it lasted for 2 days. Usually my period lasts for 4 days. Could this be my AF or implantation? I tested this morning w/ the dollar tree test and it was -. When do you suggest testing?!