Don't drink a lot of fluids now as it will do no good.You are only dilluting the urine NOT making the thc leave tour system quicker. Drink about 48 ounces of water or preferably gatorade the morning of the test.
Read the dillution stickys by IamN2pot for aspirin and vitamin recomendations.
Next time have some cheap test strips on hand. I get mine from fleabay for about $1.25 each. And test yourself before hand to see how long it takes you to get clean.
Subbing is always the most reliable method to use.Then you don't have to worry about your smoking habits. The liquid synthetic urines work very well. I always keep a bottle with me at all times.