I smoked a small amount of weed 17 days ago, 2 nights in a row. Maybe the equivalent of a bowl, total. I was selected for a drug screen today through quest (option 1, $35.00) I don't know if they are looking for thc today, I never know what I am being tested for. I am 5 foot 7 and about 300 pounds. I don't exercise. Am I OK to use my own urine, it is an observed test?