Have you tried ADHD coaching? I highly recommend it! You can find a coach on the ACO website (http://www.adhdcoaches.org/)
Coaching can be done by phone or skype, so they don't have to be in your town. You can find coaches at all levels and price ranges.
Best wishes!
You also definitely want to make sure you have an IEP or a 504 plan done for you.
There are many things you can do to help in and out of school, but I don't want to go over things that you already are aware of since you have said you tried everything.
Firstly have you been diagnosed with ADD/ADHD by a medical professional? If not then you need to arrange for someone to give you a examination. It is possible to have ADD like symptoms like forgetting things from other causes.
If your are ADD diagnosed, then...
Have you tried any of the following outside factors?
Diet
Supplements
Exercise
Medication
Or in school aids?
Therapists
Extra help / lessons
Class/learning ADD friendly arrangements and techniques
(small classes fall in here as one)
If you have tried all of these then there are a few more other options available, but I would need to know more on your situation in order to help you further instead of just rambling on.