hik- I heard the same thing - that once a person was on methadone a while, their brain changed and was never the same. We can't really know if the people writing about brain changes had also taken other drugs or have some psychiatric issue(s).
I know how you are feeling hik - I remember being at the same point you are where I had been thinking seriously that my head would not go back to normal. I'd have a good half day, then I'd feel like crap. I'd sleep better one night, then not the next two nights. My symptoms seemed like they were lasting too long for me to ever feel normal again, and for a while I seriously doubted I'd feel 100% again. I felt like my life was out of my control, like there was nothing I could do to feel better. Here I am now feeling good - feeling as though I never took any narcotic. Let mine be the story you believe - I told it like it was day after day, and I wrote it with the intent to help others like you. There is no hidden agenda in my thread. Those withdrawals go so damn slow early on, but they do go away. My last withdrawal symptoms to go away were the cold feeling and sneezing. The cold feeling gradually gets weaker and weaker until one day you realize you aren't feeling it at all anymore.
You are going to get through this, and I absolutely believe that you will be doing just fine when you are done. Keep thinking forward and get through each day the best you can. This is a long withdrawal, but it does end.
Try not to think about how long it's taking, but instead just think about "today" each day and hope that the next day will be better. You'll feel better if you sleep every night, so please get the Trazodone and ask for 150mg once a day at bedtime. You can take half that much and try it if you are leery of it, then increase it if half doesn't work. "Trazodone" sounds like some kind of bad addictive drug, but it's not a narcotic and it won't cause withdrawals to drag on longer. It will just help you sleep so that you feel better during the day.
"Why do they call it beauty sleep when I always wake up looking like a troll?"

Your friend,
Dale