I agree that subbing would be your best bet. You can get some at home test strips or go to your local drugstore chain and buy a kit since your time is limited and test yourself. Read up on both subbing and dillution. I would not go the dillution route unless you can practice it first and test yourself before you take your drug screen. Don't sweat the pre employment screen, you will not be searched or observed, you may be asked to empty your pockets. Good Luck.