Adderall is a central nervous system stimulant. It affects chemicals in the brain and nerves that contribute to hyperactivity and impulse control. Adderall is used to treat narcolepsy and attention deficit hyperactivity disorder or ADD.
It is not a narcotic although there are those who mistreat it for its affects. I'm pretty sure you'll be just fine for urine test and should not be affected by it at all.
Something is seriously wrong with your roommate.
By the way, if you got 40mg of adderall, you should have been up all night running up and down the walls and across the ceiling. By morning, it would be completely out of your system.