You're probably an introvert and need your down time. I am one. There are varying degrees of introverted and extroverted tendencies in people. They all are normal. In college there were times when I wanted to go out and party but more often times when nothing could get me out of the dorm room or apartment. But I never really felt being with lots of people was my deal. One roommate even called me a "social misfit". I was always made to feel defective as a child for wanting to spend a lot of time alone or being quiet. But I came to understand that it is just the way I roll. There is a downside as I despise networking and it is hard for me to socialize with people for personal motives like getting a job. I just don't feel genuine doing it. And many people give up easily on someone when they don't always get the response they want. But don't feel "less than" or abnormal for the way you feel. Truth be told, there are far more introverts in this world than extroverts. Extroverts just get noticed more. There are many good books out now on the subject including The Introvert Advantage and Quiet...The Power of Introverts in a World That Can't Stop Talking.