Are you saying you took the Vicodin or are you saying the test was wrong? As chronic pain patients, we have to follow the contract implicitly. It can be very hard to find a good doctor to treat you and if our pain isn't being well controlled, we have to call and talk to them or make an appointment to figure out where to go next.
As for your fall on their property, did you file any accident or incident report? Were there any witnesses to the fall? This is separate and apart from your issue with the Vicodin and you need to report the fall and if you were injured, you may want to see an attorney for advice.
They kicked you out because you broke their contract. No matter how bad the pain is you never can take more then prescribed or give your medicine to other people. The Vicodin you took was a big rule breaker unless you had permission from your pain doctor prior to taking it.
It sounds like you are not being treated well enough for your pain. If you told the doctors this and they didn't help you, then you should of found a new doctor. They can red flag your file if they think you are a drug seeker, that's why it is so important to always follow the rules.
I'm sorry this happened. You will have to look for a new doctor. Be sure to not ever take more then prescribed and always follow the contract. Good luck.