Clear blue evap?

I just want to know if the clear blue one could be an evap line. It looked like this outside of the time frame. When i took it i looked at it for the first 5 min and it was negative, and after a few hours there was this blue thin line. The other tests that i took are clear negatives. I am 15 days past my last unprotected intercourse, and today i think i started my period but it is super light. I am really paranoid. If this would be implantation bleeding, could a positive show up this early?