Could you help me find out what the name is??? ?

K i need 2 know what movie this is all i know is theres a pregnant lady and she is on a bed and she is screaming then she trys to get the phone and she steps on the floor and something drags her under the bed and there was a teen age boy in another room listening to really loud music then he didnt hear anything and he went 2 the kitchen and was making a sandwich and theyre was blood on the knife he used 2 put mayo on it and thats all i know