I'm somewhat claustrophobic, but it usually only kicks in when the limited space is due to people being all around me. I can sit in a small room just fine.
Also, its kind of odd but I also don't like wide open spaces, for example, in my bedroom, which isn't even very large at all, I have my desk creating a barrier that seperates my room into a smaller area.
Basically I get very uncomfortable when people crowd me or when I'm in an empty area.
I want to be surrounded by objects in a cramped space.