"Finish" is usually used with sports, competition, or a task like "He finished in 2nd place." or "This team finished in 5th place.". Or a parent might say to a child "Have you finished your homework?" or "Did you do your homework?". You can use "finish" when talking about work and be understood just fine "I finished my work.", or you could say "I've completed all of my work." or "I've done all of my work." which are more common phrases.
Holidays are usually expressed with the word "over". "That holiday is over." "Christmas is over."
Hope this helps.