Yes, you have to cite your sources. It's not as tough as you think though. Here are some helpful rules about citing.
When you find your notes...
If you can't tell, don't know, or have no way to determine either of the above, find a different reliable source!
...the fair use of a copyrighted work...for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include:
The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors.*
*US Copyright Office. Circular 92, "Copyright Law of the United States of America and Related Laws Contained in Title 17 of the United States Code," Chapter 1, Section 107, Washington, DC: US Copyright Office, 2008. 6 March 2009. http://www.copyright.gov/title17/92chap1.html#107