Are the Symptoms of OCD Usually Exaggerated?

A few weeks back, Mr. Stewart gave a lecture on psychological disorders and some therapies that can be used to treat them.  He also gave us a link to the page for the National Insititute of Mental Health.  I have been interested in OCD since reading this article and because of how often it shows up in the media and everyday life.  This is one of those terms, like crazy or ADHD that is tossed around and used casually regardless of whether or not a person is affected by it or not.  On the NIMH website, it says that OCD is a disorder in which a person affected has "uncontrollable, reoccuring thoughts and behaviors that he or she feels the urge to repeat over and over."  Ever since the beginning of this school year, I have been experiencing minor symptoms of this disorder, but I thought nothing of it because I thought that it was normal for everyone to experience symptoms that are out of the ordinary every once in a while.  But some of these practices have gotten to the point where they are interrupting my daily life.  For example, I'll be reading a book and I'll know that I have already read the first section of a page, but I have to go back and read it just be sure.  Also, when I lock my car, I have to make sure that I hear it beep twice to make sure that it is locked, and I am often paranoid of it being unlocked even if I know that I locked it.  I have to read and reread assignments multiple times because I'm not quite sure if I got it the first time around even if I am positive that I did.  I experience many other little compulsions that I have to carry out everyday.  Also, as per the symptoms, I have certain actions that I repeat everyday (i.e. whistling the same song all day, unnecessarily clearing my throat, etc.)  Also, I am generally a person who likes things to be neat and tidy.  I'm not looking for any medical help; I just want people to give their opinions based on what we have learned this year (psychological terms, using the NIMH website, etc).  What I'm wondering is this: Are these actual symptoms or is it just me being overly paranoid?  Could stress be a factor?  Does anyone have any other general thoughts on OCD?  On mental illness?