When you are feeling overwhelmed, you need to think of "Baby Steps". Just as a baby takes 1 step at a time, you need to take 1 step at a time. Just focus on one thing, and pretend the rest doesn't exist. Give yourself a block of time, say 30 minutes, and then stop, go do something else. It may take a little longer to accomplish all of your tasks this way, but it will definitely cut down on the frustration you are feeling.