Who diagnosed you with ADHD?is it paediatrician or psychiatrist? ADHD is diagnosed if Child is inattentive that is being careless with details, can’t maintain concentration, fails to finish tasks, poor self organisation, forgetful, easily distracted, avoidance , hyperactive with fidget hands and legs, leaves class abruptly and can’t play quietly always seems to be in rush.talking excessively, can’t wait for their turn to answer, interrupts others etc. Not necessary you should have all the symptoms. If you had at least few of the above symptoms. How long did you take medication and at what age you started taking ? Did any of your symptoms improved because as I said earlier medications improve symptoms. Once symptoms improvement and condition is stable treatment is discontinued at intervals ( short periods) which done under careful supervision of Specialist to see whether child is able to sustain progress without medication or is there need for continuation of medication.

Your problems are not clear.Please consult a Psychiatrist

From whatever you have written it is not clear as to what your problem is. Take a second opinion. Thinking can't stop because of ADHD medication. It could be some other issue , may be ADHD itself or some other problem 

Take a proper consultation with proper details of treatment taken and history