Damon and Stefan both knew that Klaus was on your trail, and they were determined to keep you safe. They knew that Klaus would do anything to get his hands on you, and they weren't going to take any chances.

So they decided to keep you hidden away, away from the world, until they could come up with a way to beat Klaus for good. You were safe for the moment, but it was clear that they weren't going to let you leave the house until things were clear.