Well, I am no doctor and I will see if I can get your post sent to a more appropriate forum.
However, I doubt that the Concerta is the problem. If you were successfully on it for two plus years, it is not going to suddenly start causing you problems. Unless, you had started taking something like Prozac or Paxill, which allows it to build up in your system. But the side effects would be different.
Also some things like orange juice taken within one hour of the medication will block its effectiveness. And a high protein diet breakfast will make it more effective. So thats something that you can easily try.
My first thought would be sleep apnea. Lack of sleep at night can seriously mess you up. Usually, you are not even aware of it. That would explain the way you feel, and why it is so hard to get going in the morning.
I certainly would have thyroid levels checked out, along with iron levels, etc. Basically, a good blood analysis looking at all factors.
You never really mentioned what the side effects were of the Concerta that was bothering you. You have gone from a mid range dose to the smallest dose. Maybe, you should try going another way to a higher dose - here again, I don't know what the side effects were. And, of course, you are taking a methylphenidate. How do you respond to an Adderall based medication?
Hope this helps a bit. Oh, you didn't say if you were on any other meds? That is important to know.
Let me know what you find out.