A drug test with a "Drug Assessment" coming up

I'm taking a drug test within the end of the month for a drug assessment that I was ordered to do by my school. I smoked 6-8 times between August 20th to September 3rd, while smoking about 2 times after that during the month of September, the last of which being September 26th. I took an At Home drug test made by First Check using my second void of the day. It came out Negative with a line slightly less solid than the check line(I can't remember what they called it, it was the one that confirmed whether the test was working OK or not). The void was fairly yellow and I hadn't done anything to make it that way(that I know of).

I'm about 5'8.5" and I weight about 200 pounds, so i'm fat(not obese or anything).

Do you think i'll be ok? I'd also like to know what this assessment will entail, and the possible consequences of failing this test would be(or telling them that I smoked after I got in trouble on the 3rd).