Is this normal for FRER?

Jennifer • Hopelessly in love with my soulmate, mother of four beautiful kiddos: 💕03/03/08, 💙05/06/10, 👼💙09/28/18 - 06/02/2020, 💙03/27/2022 and current expecting #5 in July

I am 4 weeks and 4 days. I have been using the strips to watch line progression but now that the strips are as dark as they are going to get I bought another First Response to see if there was a line difference from when I was 13 DPO (at that time test and control were equally as dark). I took the test this evening and the result is a very very dark test line and a very very weak control line. Is this normal or is the test faulty?