Honestly dude, if I were you I'd go smoke a fattie. There's no point in stressing cuz there's no way you're pissing clean. Better off light one up now, not worry and start coming up with ways to 'talk your way out of it.' You'll need to express that you are responsible, remorseful and rehabilitating. Just be honest and maybe you can squeak yourself out of this one. You'll still suffer some consequences obviously but you can save yourself a lot of trouble if you just play it cool. After all, the national view on weed is quickly becoming liberal.