Dealing with the downs?

I realize that this is largely a venue for behaviour training and not for behavioural modification - but I think this can apply across a lot of aspects of dog (people/horse/cat etc) training... 

I'm not a professional trainer, just someone with a couple dogs learning and growing together. I have Blue (a rescue that I've mentioned in the past) who is very concerned/anxious/reactive and we've been working (a lot of it with the clicker) on behavioural modification. And today we're having a rough night - Blue has decided to be upset about something in the environment (I didn't catch what triggered him) but he became spun and once he's there, its a struggle to get him "down". Presently he's in his crate, with a stuffed frozen kong, and I hope that when it comes time for bed that he'll have a full tummy and have long forgotten what has spooked him. But it's hard to see him like that. Especially following a few awesome days (and weeks of moving forwards in leaps and bounds) - and I know I'm not the only one that gets "down in the dumps" when they hit the low aspects of the "highs and lows" of working with dogs (people/horses/cats etc :), when the end behaviour seems nowhere in sight, and you know it may be best to take a break and walk away, because pushing will get you nowhere.

So, how do you guys deal with the downs? 

I know I personally have a VERY difficult time walking away from a problem, and even now that Blue is safely put away and occupied - I am STILL resisting the urge to go take him from the crate and work on our problems (despite knowing that that is not the best thing for either of us, and I know I won't - but I keep feeling compelled to do so) 

help!