Very positive FRER, but negative first response digital?!

Jessica

Okay ladies I need some help! I have been testing all weekend and my lines are getting darker and I am 12DPO. I took both a first response and a clear blue (both digitals) and both of them came back negative. I took them apart and there were dark(ish) lines on both.

Has this happened to anyone else?!

Should I be worried?

HELP!