Line not getting noticeably darker

Evan • 26; married 6 years; #1 born 2/7/16; #2 born 11/5/17
I'm currently 4 weeks, 3 days. I am beyond nervous of a chemical or MC, as I had an early MC in February. It seems like my test lines aren't getting much darker. I've had a positive digital, but it still makes me anxious. Pics AR in chronological order, taken over the last few days. Any advice?