Go in... in a good mood. Maybe bring a music player if you are nervous to try to keep you calm. Think about what keeps you calm. Let them get it done. Maybe close your eyes while they do it. Heck, take off your shoes in the chair, try to be comfy while they do it. Once its over you will feel SO much better. Don't dwell over what you know you won't like. If you know someone who has had this go on... Ask them to tell you what to expect. That way you aren't overly freaked. I know I would be freaked, so understandably, a little bit doesn't hurt to be freaked. Educate yourself before you go. If you want someone there, nobody will make fun of you for having someone there or holding your hand. Its freaky doing something new.