Should I be worried?

I'm 7w4d and just took a FRER for the fun of it, because I had 2 left. Well the control line & the test line is the same color, ones not darker than the other. 
At 5w5d, the test line was so dark it took the color from the control line. 
I had my first US at 6w2d and the baby is healthy & has a heartbeat. 
Should I be worried the test line isn't darker now?