Clouds and Enthusiasm

I think it is safe to say that I am trying to find my way of a cloud of depression again.

My enthusiasm for doing almost anything at this point has evaporated. Things that I previously enjoyed seem gray to me now, something that I have to work up to doing. The thought of doing almost anything I used to enjoy seems to be a burden now, something I really have to work up to do.

I wonder if it is simply an extension of the way my life seems to working through other things currently:  a long sense of endurance, of doing without the belief that anything will get any better, rather than a sense that I am improving or making progress in anything.  When one is doing something because one has to and there is no realization that anything is getting better or one is getting better at it, there seems to be a significant loss of enthusiasm.

It is not a question of recognizing the issue.  It is a question of what to do with the issue.

How does one generate enthusiasm for anything?  This seems to be the core question.  How does one take where one is, look to the land of where one wants to be, and then find the fuel to take one there?

It has to be something internal.  I get that.  Trying to rely on outside circumstances or outside people to get the drive you need to succeed in anything will never work.  It has to come from you to weather the times when circumstances are against you or people are non-supportive or non-responsive.

The question is, where does one find it?