Really worried about line progression 😔

Top test is 9DPO, next is 10DPO, then yesterday, and the bottom is today. The bottom picture is just yesterday and today. All FMU.

Today’s test appears lighter than yesterday’s. With both of my pregnancies, it was super dark by the next day. Anyone have this and go on to have a successful pregnancy? Or should I worry this is a chemical? 😔