I don't think this is weird, I have the same thing. I have used the phrase 'switch' to myself before too.

Sleep (if I can), exercise and humour always help me when I blue. Also talking to a friend who is not involved in the situation helps.

I find using external sources such as the above work well. I try not to mentally defeat the negative feeling internally as it doesn't usually work for me (although hats off to people if they can change this. NLP etc just isn't stong enough for me in some situations).

I usually just tell myself there is a chemical in my brain caused by a random bad event. This chemical is the reason I feel bad, but it will soon be out of my system and then I will feel good. I know these 'events' happened before, but they do not seem as big a deal as the current event (even though they were at the time) as their chemical is dead.

Also remember you have had many 'good chemicals' in there too caused by 'good events' and the next one of those is just around the corner! In fact think of past 'good events' now - might help (hmm maybe 'NLP etc' does work!)

Oh and back to my point, sleep, humour, exercise, socialising with close friends all release endorphines, which to me is a good chemical too and why I think they help you feel happier sooner again! There are also many other things that do too, but these are usually the safest for me if I'm feeling down. Talking to a new girl for example could bring me up, but also has the potential to bring me down further. I usually like to improve my state a bit first.

Um, if you've not guessed by now I am by no means a scientist, so take my advice with a pinch of salt still please! Works for me though! Probably should give the books a try too, they sound quite useful.