I usually define it as the blahs actually....the gray area not so depressive really but, just blah and certainly not up perky and chipper or anything good feeling at the same time.
I try to take a moment to figure out what it is thats bugging me....then go from there.
It all depends on what the situation is really.
If its a weekend and Im home and just notice all of a sudden that Im blah...I think about what Ive done or havent done to get me into the mood. I could have spent an entire afternoon watching movies and am telling myself really that I need to get something constructive done...get this kinda goes with the scrubbing floors method cuz start doing this that and the other thing until Im to the other point of blah where I figure out I need to stop and sit on the couch cuz Im doing 300 things at once like an idiot.

I could just be driving in traffic and find that I am seriously stressed out for no immediate reason. When thinking about it I have had something go on, a stressful day, a lot of planning for a trip, an expectation, something thats making me blah that I need to change so...I smile at the person next to me who looks like they've had it worse than I have...put on the metalhead music and sing and dance tomyself...just be a little off the wall...strange how that helps get the funk out.
A great deal of the time though it'll be because I havent spend quality time with someone inparticular..a SO, friend or family member...so I get onl ine and send a note, pick up the phone, offer a movie...something like that and its great how connecting with others makes you better.
There are those times however I know better than to talk or spend time with anyone and usually just need to unplug and unwind by my lonesome for a bit doing little bits of things...paying bills, doing dishes, playing with the cats, listening to music, or something creative with the photo stuff.....I have found that grabbing the camera and going away makes a great deal of days better no matter what the mood when the sun rose.
I think mostly really we all feel a bit out of balance and have to do something that equals the scales out more to feel better.
Taking a few minutes every morning to talk to the cats, as strange as that sounds, has made mornings a more lovely affair..traffic or not, coffee or not, Monday or Friday...whatever...a little time to enjoy the good things in life when you run around trying to live it makes the balance more equal.