Both the forest and the trees are important. When you feel overwhelmed, pay no mind to the whole project, the whole of your life, etc. Look for one small step you can take. The best one to choose is one that will take 5 minutes or less. You need a small victory and you need it now. Build up to bigger steps. Once in a while, step back and look at the whole. Never let one of them make you lose track of the other.