You may be ok because you will have 29/30 clean days, I was a very heavy smoker and passed a urine test at day 22,
best thing to do is buy some home tests and see for yourself if you can pass. Excercise a lot too, but NOT for the 2-3 days before the test as excercising will release the THC metabolites from your fat cells.
Drink water/cranberry juice on the day of the test and do not use your first wee of the day.
As far as I can gather that is all you can do. Do not waste money on "cleansing" products I've not heard one good review,

Read the sticky threads on dilution and substitution, they cover everything you need to know for a urine test, you should be thankful it's not hair like me, I have the same riding on my results.
Good luck