While your clean a one time smoking session could last 5-7 days. I wouldn't chance it with only two days to get clean unless you want to substitute. Freezing your own piss would be a wise idea if you know its clean. If you want to be totally safe and sound I would pick up a bottle of QF and smoke as much as you like. Given your height, weight, and metabolism i would say you wont be clean for atleast 3 days. My personal opinion would be not to risk it and abstain from smoking, but if for some chance you can't or won't then get some QF.