My first "positives" were on Wondfos at 11DPO, and almost exactly like yours - the faintest of lines showed up just past 5 min. The lines got darker over the next couple hours. I never had anything like that on BFNs. Not saying you should trust these, but I'd say it's looking good for you!
I tested later that day with an FRER, and a definite line showed up within the correct time frame. Like other PPs suggested, I'd say go get one - or actually, I'd get a 2- or 3-pack, hold your pee for a few hours, and test tonight, and then confirm again tomorrow with FMU.