No you're not alone in the feeling that you need your space. It's ok to not like someone and some people are just incredibly annoying. Maybe something you said or did gave her the impression that you want to be all buddy-buddy but you don't so you have to let her know. Don't spend the whole time making it a bad experience by hiding in your car, etc. Just muster up the guts to tell her you need your space. It might be awkward and uncomfortable at first but after a bit, it will go back to normal.