First, recognize stress:

Stress symptoms include mental, social, and physical manifestations. These include exhaustion, loss of/increased appetite, headaches, crying, sleeplessness, and oversleeping. Escape through alcohol, drugs, or other compulsive behavior are often indications. Feelings of alarm, frustration, or apathy may accompany stress.

If you feel that stress is affecting your studies,
a first option is to seek help through your educational counseling center.

Stress Management is the ability to maintain control when situations, people, and events make excessive demands.What you can do to manage your stress? What are some strategies?

Look around
See if there really is something you can change or control in the situation Set realistic goals for yourself
Reduce the number of events going on in your life and you may reduce the circuit overload

http://www.studygs.net/stress.htm