With regards to my ADHD meds, I have taken and take every stimulant/non stimulant made, all forms working to then suddenly just stop working at all! Why?

ADHD. There may be several reasons, most common is tolerance to the drug, hitting a therapeutic ceiling. That means you can't go higher on dose. Depends on how they were rx'd. One method to help is combining meds of different classes that enhance each others' benefits without risking toxic side effects. That helps avoid tolerance, & greatly increases your options .
Habituation. It is not uncommon for a previously effective med to stop working successfully. Some psychiatrists have a staggered approach to this problem where for 6 months or so a person is on one medication and then switches to another one. Talk to you doctor about these methods. They can really help.
Tolerance. Your liver is designed to destroy the drug once it is absorbed. It takes a while to find the right enzymes to destroy the adhd meds and build the enzymes up to high enough levels. Once that is done the meds won't work. Are you following your joy and pursuing your passion? Go here to learn more http://www.Adhdoractivechild.Com/.