pain levels absolutely 1000000% compound depression issues. My mom's doc (and my new doc) have gone over this kind of thing pretty extensively. The problem actually is that your baseline is actually "I hurt really bad". When that baseline dips to "not in a lot of pain" you get super productive YAY. When the pain comes back to your "normal" it drags you down without you realizing it. The only time you really understand and realize it is when, you know, it flares up.

And sadly, with your work schedule it's not like you can just take a day off and lay on the floor.