Make a detailed schedule for a week in a daily planner sheet including consistent time to go to bed and time to wake up. Budget your time in a day between wake up time and bed time. For example: Monday=50% school, 25% work, 10% volunteering and 15% for household and personal necessities; Tuesday=40% school, 35% work, 10% volunteering and 15% for household and personal necessities; Wednesday . . . Then enter those actual times you do those budgeted activities in your daily planner. Place your schedule/planner in a place where you always go to like bathroom mirror. You have to be strict to yourself to follow your schedule. Whenever you have extra minutes from your allotted time for school or work, use them for your personal needs.

I hope that will enable you to have proper control of your time to reduce stress.