"I worry about ...": active voice; 'worry' is verb.
"I'm worried about ...": active voice; 'worry' is adjective NOT past-participle verb!
"I'm worried by ...": passive voice.
Also see: http://forum.wordreference.com/showthread.php?t=558913
American English, the verb cancel is usually inflected canceled and canceling
In varieties of English from outside the U.S., including Canadian, British, and Australian English, cancelled and cancelling are the preferred spellings.