I'm sorry you're going through this hun.
I can only speak from my own experiences, but I used the first signals for several months ttc sophia and for a couple months ttc this one. I only had lines when I was pregnant both times. I hate to say it, but you know your body and it sounds like a chemical, although I know it would be more pleasant to just think it was evaps and not really picking anything up at all. the lines on first signal and frer were both clearly there so it seems odd that both tests would have had them around the same time, and then both not have them anymore after iykwim?? not trying to make you feel bad, you know I'm praying for you, but just my take on it is that you aren't crazy at all.