Pain
"I was given  nortriptyline by a pain doctor 7 years ago. It did help somewhat with the pain.
However the side effects have been giving me problems ever since. I have problems concentrating but worse than that I daydream constantly.  I can&#039;t shut it off. It lasts for hours. 
It is like it turned on a daydreaming switch in my brain and I can&#039;t shut it off. I went off of it expecting it to stop. It never has. It gets more unmanageable. I do not know what to do."