I would trust an FRER over IC any day of the week. I bought IC to use to quell my poas addiction. When it really, really counts, I FRER. Now, I have gotten a true bfp w/IC and it was faint, next day was dark. I confirmed w/FRER anyway, because I still didn't trust it. I have also gotten colored evap lines w/IC. Their OPKs however, are the best I've found for me and not getting false pos.
I am definitely going out to get a FRER today. All my IC HPTs have come back faintly positive (although it does look like they are getting slightly darker). My bbt has also gone way up the last 2-3 days (from 98.4 to 98.9!). I am hoping this is my month and that this one sticks!
With FRER when it is neg there is no doubt. The white is so starch you can't even trick yourself into seeing a line. Sounds to me like you are BFP but spend the $ on FRER and stop torturing yourself!! Let us know how it goes!!