So, after I take care to be sure I get in bed early and have adequate exercise, etc, what do I do if the sadness persists? I am no counselor but I have found some things that are helpful. Other than considering the physical aspect of "the blues", I go through a list of strategies and apply them.
2. Embrace the truth that, as Christians, we are commanded to rejoice. In the Lord. This means we are to be happy! So we need to learn how to do just that. It helps me to understand that this desire to be happy is really a longing for Christ. In His presence is fullness of joy. So I must realize that if I am experiencing despair or despondency, I must accept responsibility for it and do what it takes to be obedient to His command. While I don't think this means we are to expect a circus euphoria perpetually nor does it mean we should be deceitful to ourselves or to others when we feel this lack of joy, I do think that we need to take seriously the need to find our joy in Him.
That said, what are some ways to accomplish this?
3. Stop blaming others and stop looking to others to "fix things" so we can be happy. This is alot easier to type than to practice. It is very natural to feel that some of our lack of joy is a result of the actions (or inactions) of others. This may be initially true but it blaming others serves only to prevent our reaching the goal line of happiness. It is probably the biggest block, in fact. Expecting others to take responsibility for our joy is immature and ineffective. In short - it just won't work. Ultimately, it short circuits not only the relationships where we place the blame, but most other relationships as well. After we pass about age 3, other people just won't accept the burden of making sure we achieve our goal of joy. That obligation takes a dramatic shift towards ourselves. And the sooner we accept that, the happier we - and they - will be.