My Puppy got into a bad of Adult dog food!?

My 12 week old, 25lb dog just got into a bag of adult dog food and ate over half the bag while we were out for dinner (stupid, forgetful boys who don't put things away). Her belly is pretty distended and she has been drinking a lot of water and acting a little funny. Is there anything I really need to be worried about or will she just feel bad like anyone would if they over ate?