I've just stepped down from some voluntary work I've been doing for a few years - given lots of time (probably to the detriment of my family) and some expense too. I gave the other people involved lots of notice and in fact was persuaded to carry on for longer than I wanted to. Now I've stepped down, everybody involved knows and not one person has thank you for what I have contributed. AIBU to feel a bit 
and actually rather a mug for having given so much in the first place.