Is Donald Trump finished?

[Why]

Trump has to win New Hampshire, which going by the polls he is going to do easily.
In Iowa he was first headed by Carson and then Cruz. Although it seemed he had regained the lead in Iowa it was still not a huge lead.
His biggest threat is probably not under performing for the poll results, although he might do that again by a bit, but if the Rubio's performance gives Rubio a huge last minute surge in New Hampshire. Still it would be a massive change in a week to see Rubio beating Trump, one I do not expect to happen. Rubio might get second well ahead of Cruz.