Do you mean worried about anesthesia? I would say educate yourself. If you are using the internet, read reputable sites (my hubs of course) like webmd or the American Society of Anesthesiologist website (www.asahq.org) and NOT the stories of things that people write on their blogs or forums. Some people have had bad experiences, no doubt, and some are related to anesthesia, but some of the things they attribute to anesthesia aren't really related at all and it confuses the issue and leads to misunderstanding and unfounded fears.
If you have an upcoming surgery and you are overly anxious about the anesthesia, ask if you can talk to an anesthesiologist ahead of time to discuss your medical conditions and your anesthesia options and get your questions answered.
Good luck and let me know if you have specific questions.