Meditation can help bring you back to the task at hand. As for the gloom & tiredness, I have a light box that mimics the spectrum of the sun; sitting in front of it for 30 minutes ago gives me a burst of energy most of the time (but there are also times when my depression is too deep).

I'm sorry your son might have an ear infection. My kids are grown, but I remember how fussy & miserable they were when their ears were acting up (my daughter's ears were so bad she needed tubes). Anyways...I hope you can reach into your reserves & make it until you can go to bed tonight. Good luck.