Adderal is an amphetamine, but it shouldn't test as "meth" in a good drug screen.
I happen to have a urine drug screen form right here, you can test "negative". Or positive for cannabinoids, cocaine, amphetamine, methamphetamine, opiates, etc.
The amphetamine and meth are two different "check boxes", and you should have tested positive for amphetamine. If you have a prescription in your name that shouldn't be a problem.
Best wishes.
Your probation officer should know what medications you are on. Yes, Adderall is stimulant based, its a methamphetamine. You can look it up online to get the information. You should have a doctors letter stating that you are on the adderall or have your doctor change you to Stratterra which is a non-stimulant treatment for add/adhd, especially in adults. I wouldn't be too worried, but if you don't want to test positive all the time you might want to try something else. I don't believe they can further test your urine or blood to find the reason for the meth in your system and its exact nature, its meth no matter how it got there, legally or otherwise. So see your doctor, get a letter or have him try a different medication.
Good luck, stay out of trouble.