There are at least 12 possible causes for your situation. If you answer yes to any of the next four questions it may help identify the cause.
Have you started on any medications recently? Is anyone in your family diabetic? Have you been doing any heavy drinking? Do you use recreational drugs?
No matter what the cause, most shaking (called tremors) does occur during periods of heightened stress.
One ailment, called "essential", "familial" or "senile" shaking can occur during a lifetime, and is poorly understood. It has no obvious cause, but usually involves twitching of only one hand and the head.
If your twtiching also involves the tongue, you may have an overactive thyroid. It sounds as if you are a student, so check-in with your student health organization, and advise them as to any question you answered with a "yes".
I am a medical researcher.