I just started on generic Concerta switched from Ritalin. In my research I found both drugs are the same with one exception,,the Ritalin was immediate release and Concerta is extended release.
I know what you are going through though. I had the same issue with Adderall, there IS a difference between manufacturers. Teva was the only Adderall that worked for me. But as you found out no one believes you and they say it is in your head. I was ok, so it is in my head so give me what I think I need then so that I can function ..please.
I know I am not providing any answers just trying to be supportive and remind you that you are not alone.