Depression as a side effect

I've heard about depression often being a by-product of serious illness and I've experienced it firsthand -- a little post surgery blues that dissapated when I started feeling like my old self again. But it didn't occur to me that it could be a side-effect of caring for someone who is ill. The possible causes are (1) the grind, because it does get old, (2) feeling helpless or overwhelmed and (3) realizing that your efforts are wasted is so far as making someone better is concerned. In the past few days I have discovered another cause of depression and that's knowing that time is short.

Several times a day, I try to get Mom to eat. She might have eaten a tablespoon of yogurt for breakfast. A little later I had some luck with ice cream. She might have eaten a quarter of a cup. Later I tried a milk shake and got maybe a tablespoon into her. Several times today she drank water or coffee but not much. She takes the straw in her mouth to please me but does nothing with it. I don't know how long this can go on. But I think, it can't go on for very long.