これは "worried about" もしくは(ちょっと不自然ですが) "I worry", "I'm worrying" ではないでしょうか。
そして、
"you look like having 〜" だと思います。
そもそものご質問、「余裕だね」については、あまり「これだ!」というのが浮かびませんが、
You don't look nervous at all. Must be prepared!
I wish I could be as confident as you are.
How can you be that confident?
You are not concerend about tomorrow's exam, are you?
Oh, you must be well set/ready/conditioned!