Reassurance

This is long but stick with me:

Fingered on Feb 10. May have been some precum on his hand but im unsure if he wiped it off. No sex at all. Period was due the 19th of February and I got this:

Moving to yesterday (day three) blood still going. Some times in large strand i took a test today with first response and got a negative. My period seems lighter but I’m not sure if its all just stress.

Today woke up and its super light. My cycle is normal 6 days and today is only 4. Is it stress? Could this be implantation? (I know some people say it’s possible to have it heavy). I just dont know