If you see a hint of something tonight I'd say go out and get a FRER. FRERs showed my early early BFP way better than Wondfos did this time around, but I wouldn't drop the $$ unless you're pretty sure you're seeing something, know what I mean?
They are just SO expensive, grr. I wish they would just sell the FRER strip without all the plastic casing, like a 10-pack for the same price as the 3-pack!