Is this normal for FRER?

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?