Time management is very difficult in this day and age. You have to check your personal email, work email, get the actual mail, facebook, hubpages account, laundry, dishes, eat regularly, eat healthy, clean the litter box, let the dogs out, and that is not even related to school and work.
Take some time to breathe. Learn some breathing exercises. Listen to calming, relaxing music. Find out what causes you to enjoy yourself without getting stressed.
Know your priorities. Which comes first, school or work? Which is more important?
Do one thing at a time. Multitasking can distract you from what you are trying to do. Learn how to create balance.