Goodness! So sorry girl
it really is the strangest thing...I dont think it matters if you are 7dpo, if the test picked up hcg and formed a line then there would be progress from the minute it showed up on IC. Once its there and real it only gets darker. My guess is that perhaps theres a strange hormonal surge at the same time in your cycles that somehow causes lines to appear? The only other possibility is a chemical. Im really sorry you have to go through this over and over its crazy! FX for a sticky bean soon xx
After having a beta return at <1 a while ago when I was still seeing lines on tests I'm assuming my baseline hCG level is normal, so I don't think there could be any hormonal surge unless in the case of PCOS, I know some see false positives I think because of cysts? I don't have this, so can't be that.
I don't know what ICs are like where you are, but here their reviews are mixed. A lot of people with convincing lines which aren't real as they used other brands which were negative, others saying they gave false negatives, others saying they were good so it's chance with those I guess. I know CB can give false lines.
Fertility Friend would have put me at 5dpo when I had those lines Monday, so going by the app I am 7dpo today, but I put myself a day ahead as I believe I ovulated on CD12 rather than CD13, so could be false lines, or could be a chemical, time will tell