You have to be a bit mor specific. What specifically are you anxious about? You can't go in there comparing yourself to anyone -- especially the really rock hard people. Those people probably have genetics on their side to begin with, but they probably put in a lot more time than you or I are willing to. They're probably their 5 times a week or more. They probably are willing to get by with a slice of bread and water to look as slim as they do. If I was willing to do all that, I could look like them too. But I need to have my Ben & Jerry's (ice cream NOT frozen yogurt). I go through a pint in 3 or so days, sometimes less, sometimes more. So far, I can get away with it. But, I'm at the gym 3 days a week. My workout is proably at least an hour each day, and I try to keep my sets in close succession to keep my heart rate up.
Set a goal and focus on it. Shut out everyone else.