Supposedly the budget for the movie was $200 million. With US opening being pretty weak around 30million, I can't imagine this moving making money.
That's unfortunate because I really enjoyed the movie. And according to Rottentomatoes, it looks like users in general liked the movie but did okay with Critics.
If you go by US box office standard, yes it was a flop. The chance of the movie getting a sequel is low. The only way it would get one is if James Cameron, who produced it, really pushed for it...