Nap or sleep

Last week I was sick all week, I'm still coughing up stuff actually. One day I came home from teaching and was positively exhausted. I didn't have to teach the next day so I decided to take a nap. It was about 11 am when I laid down and about 3 pm when I woke up. After that nap I was wondering if it was still a nap or that really sleep. What separates the two?
Anyway this past moth has gone by incredibly fast. I had my close of service conference (COS) and after that I went to Vienna and Budapest where I met my sister. The conference was probably the last time that I will see allot of the people I have come to know over the past two years. It was strange thinking about that. One of the things I have thought about recently is that when I go back to the states I will be with a bunch of people who won't have had similar experiences that I have had over the past two years. In some ways that will be a welcome change and in others it will be a loss of a unifying experience that I have really come to enjoy.
Vienna and Budapest were both beautiful cities. It was great to see my sister again. We had a great time, although I think I annoyed her with my lack of preparation and laid back attitude. Thankfully however she was a great sport about it and is used to putting up with me.