help! need advice

I recently got my dream job at a hospital. I smoked last on June 5. My drug test (urine) is on June 28. I know that this is enough time to probably pass but I will not gamble here. I am in nursing school and if I fail I will not only lose the job but they will tell my school. I went to a head shop today and bought an at home THC test. I tested negative. I have to go through a whole physical exam and this is at the hospital. I am wondering if the drug test they will use is stronger. My friend said it probably is a mass spectrometer. The detox they recommended was a drink that you drink 2 hours before the test. Anyway... What do you all suggest I do?

Any advice is well appreciated!

Read my post in this thread:
http://boards.cannabis.com/drug-test...g-program.html

Be sick, break a bone, get a concussion.

I passed flying colors.
I used xxtra clean detox sour apple flavor drink. I drank it at 5:30 am my test was at 10:30. They gave me instant results and I was clean as a whistle