What happens when you don't feel appreciated?

Anyone can share? This happens on a daily basis for me.

Working in a small company means that we have to do tasks not prescribed to us because we have only ourselves to count on or to blame on if anything is amiss.

I don't have a problem working on things that are not inherently mine. In fact, I love doing it simply because of the reason that I can learn new skills and it adds to my experience. The problem that I do have, however, is that I'm not being appreciated. Even worse, I'm being picked on. It's times like these that makes me feel that I need a vacation...

Maybe even a new job.