HCG after D&C

I had a d&c on Jan 16. I've been using easy at home pregnancy test strips while I wait for my HCG to go down. They were very very faint the last couple weeks until I thought I finally got a negative on Monday Feb 25:

I've been waiting for my period to come, which I thought might start soon since I had some cramping, mood swings, acne, and brown CM on Tues this week. I decided to test again, unfortunately I ran out of cheap test strips so I took a first response and got this:

Yesterday:

Today:

I'm trying not to get worked up. I'm thinking it's still left over from the miscarriage. I'm planning on testing again in a couple days to see if it getting darker. But I'm wondering if anyone else has tested negative with an internet test strip but still got a positive on first response? Do u think this is still left over from my miscarriage?