was it implantation bleeding?

I had my period on the 7th of this month. Then on Friday I had spotted brownish color until Saturday then it stopped. It was way too soon for my period so I decided to go ahead and take a test. I took one last night and it look positive, but it was a faint blue line. How long after you have spotting can u take a pregnancy test? Could we hopefully be pregnant? My back hurts, and I am having light period like craps. So I am scared that I imagined the extra faith line. What do u guys think?