How will a body react from a prolonged sympathetic nervous system activity?

Question

Such as suffering from sleepless nights and loss of apetite, thinking about examinations and tests..

Answer 1

According to SleepNet.com (1):

"People who don't get enough sleep may lack energy, be depressed or irritable, have trouble remembering everyday things, and get sick more often than people who get enough sleep. They seem to age faster and they may have problems concentrating at work or school. Some scientists believe a lack of sleep may have a role in diabetes, high blood pressure, heart problems, and even obesity.

"Poor sleep also leads to accidents. More than 200,000 auto accidents happen each year because drivers fall asleep at the wheel. The 1989 Exxon Valdez oil spill was at least partially caused by the actions of a tired tanker operator."

and Wikipedia (2):

"According to a 2000 study published in the British scientific journal Occupational and Environmental Medicine, researchers in Australia and New Zealand reported that sleep deprivation can have some of the same hazardous effects as being drunk. Getting less than 6 hours a night can affect coordination, judgment and reaction time." (2)

Lack of appetite will eventually cause weight loss (no surprise), but has the more immediate effects of irritability and inability to concentrate.

All in all, I'd say that neither sleep deprivation nor anorexia are going to help with those exams. And (seriously) I haven't been getting enough sleep because of a medicine I've just started, or I probably could have found more relevant answers. I'm "not all there."