Good question, Paul!
i know what is "normal" for me - that is - how i usually react to triggers or memories or the painful feelings that come up - sounds like that is what you are describing. that is not necessarily the way others respond - but i think there is enough commonality that we can all relate.
what you have described very well is the way i used to feel too. then for a while it was less ups and downs and more like a constant deep pit. BUT now i am at a stage where the "troughs" are not as low and don't last as long. and some of the highs are higher. last week i realized at one point that i was feeling as calm and relaxed and good as i only used to feel after having a couple drinks. and i hadn't had a thing to drink - honest! that was a great feeling!
so - yeah - if there is any way that "normal" can be used in this context - i think that you are right on. maybe a better term would be "typical" or "predictable." bottom line - it can/does get better with time and work. (and i gotta say - my version of "normal" changes as i learn to deal with and overcome all the bad stuff!)
hang in there... you'll make it!
"My experience has shown me that I all too often tend to deny that which lies behind, but as I still believe, that which is denied cannot be healed." Brennan Manning, "All is Grace - A Ragamuffin Memoir"