feeling down

Just can't seem to shake it.  Ever since we did our presentation ~ I've been feeling depressed.  We have another program coming up this Thursday and I have no desire to work on it or even present it.  
That said ~ I don't think my depressed state is a direct result of it.  Not sure really where it's coming from but I am trying to think positive.  
The only time, in my adult married life, I couldn't shake "the blues" was when my son's were going through their trials ~ but that was a few years ago.  Even my middle son's latest scary episode this past summer didn't make me feel the way I'm feeling now.
In fact, I thought the soccer game with the gorgeous weather would have jump started me to get me back on track but ~ no.  
Hope this passes soon because I am normally a positive person with a lot of enthusiasm.  Maybe writing this out will help.