Drugs like amytritaline are not meant to be taken for extended/regular lengths of time. I had similar to what you have described, and noticed that it made my mood more negative too. So I stopped taking it and felt better. My understanding is that this is a common reaction. Hopefully you are ready to forge your own sleeping/energy pattern, but if not your Dr will be able to discuss/prescribe an alternative.

(Those symptoms/advice should be printed on the inner label thingy)