Darker tests during chemical

Over the weekend I started having heavy bleeds/cramps with small but many clots. My bleeds weren’t heavy enough to fill a pad but resembled my period. The nurse I spoke today suspected that I’m having a chemical, however, I can’t get an appointment until Thursday to determine anything. Pregnancy was confirmed by HCG levels and positive tests.

I tested on Thursday (28/07) and Friday (29/07) and started bleeding that Friday night. As I couldn’t get an appointment I tested again Sunday (31/07) during my bleed and my tests came back darker.

Has anyone who has experienced a chemical had this happen to them???

Thursday 28/07 (top test) and Friday 29/07 (bottom test).

Sunday 31/07 during bleed (bottom picture)