Barricade (2012)

A year after his wife dies, Terry brings their children to an isolated cabin in them mountains that their mother used to love.  And by cabin, they mean a huge home.

Terry instructed the store owner to decorate for Christmas, so there is a tree all set up, and the kids favorite foods are plentiful in the freezer in the basement.  The next day they head out to play in the snow before a storm rolls in, but think they see someone outside.

Strange things start happening. Someone dumps toiletries all over the bathroom and Terry's medication disappears.  The kids are getting nervous, and everyone is getting the strange cough that the store owner had.

After seeing someone running by the shed, they bolt back to the house and lock the doors.  Terry decides to barricade his family inside to lock out whatever menace might be out there.

It's not clear if: Terry's missing medication means he's going psycho; everyone is coming down with a mystery disease that alters their reality; the cabin is haunted by an evil presence; or someone is truly outside stalking them.  When you find out what's going on, you'll be highly disappointed.