Chemical Pregnancy or Trigger Shot?

Top picture was Thursday— my trigger looked about completely gone. Middle is Friday morning, bottom is Friday evening. I figured I had to be pregnant because my line looked darker (I asked several people and had some look in person, and all agreed it was darker).

Now my tests are COMPLETELY negative.

I had a little cramping and one sharp pain on Friday night. Could this have been a chemical pregnancy or do you think it was just the trigger shot leaving my system?