Yeah, Quick Fix is for sure the way to go, for me at least. I keep some on hand so I'm surprised by anything
With this much notice, all you really can do is drink and hope it's enough. To be perfectly honest though, I'd be a little worried. Going from non-stop smoking to piss testing within like 3-4 days is shitty. If you do pass, I would probably credit the stuff you got at GNC. I wish ya the best of luck though man, make sure you let us know how things turn out for ya.