Another place to look for 5k races is Running in the USA.
http://www.runningintheusa.com/Race/Default.aspx
Also, I completely agree with everyone saying to slow down. In college, some of the my sorority sisters and some of my roommates would try to get me to run with them. I hated it, because I would get so out-of-breath so fast and I would feel like I was dying. Once I learned to run at my own (very slow) pace, then I found running much more enjoyable and more comfortable.