I would also say it's really possible too that your response to the pump has dwindled a lot, but your supply is not necessarily as low as your pump output might otherwise suggest. My pump output is quite low at this point too, but I don't think the amount of milk my daughter gets when nursing is anywhere near as low as my pump output at this stage in the game suggests it is.
I don't think it's weird to be sad about your supply going down, either. I'm sad every single time I feel like my supply has adjusted downward as our nursing relationship progresses. I think a lot of that sadness is because my daughter is still such an avid, frequent nurser--of course I will always allow comfort nursing regardless of the amount of milk she's getting, but I too also really know my daughter loves the milk itself, so I completely understand how you feel about this!