One Day at a Time and First Things First! Of course, saying these is a lot easier than doing them!
When I get overwhelmed (and manic), it helps if I can try to just take life one day at a time, and to set priorities of what I need to do now or first, one thing at a time ("First Things First"). Trying to multitask when I am overwhelmed doesn't work for me. "Do the Next Indicated Thing" is another 12th Step slogan that helps me when I can't figure out where to start.
Good luck!