Redefining "Me"

I need to figure out which parts of who I used to be were the Bipolar II or Cyclothymia or whatever and which parts were really me, so that I can tell whether the Lithium has taken away those parts and left me as the "correct" version of myself, or if it's not working. Part of me wants to blame all of my faults on the disorder, and if the Lithium really is working, then I can't do that. How do "normal" people feel? Explain to me the difference between happiness and mania; between being down and being depressed. I know that in the end it's just something I'll have to figure out. It's just hard on days when the only word I can use to describe how I feel is "weird."