I believe this was a British film, pretty low budget. A couple is in their apartment and their male friend comes over pretty upset. He tells them he’s seeing stuff in the house, like monsters. The couple is unsure if he’s going crazy and begins to get scared. But then they begin to see the monsters outside trying to get in. At the end they end up hiding in the upstairs apartment and there is some ghostly lady  and crying a baby  and its all bloody. I believe the lady stabs her husband on accident in the apartment. Everything takes place in the apartments. I think it turns out the friend had killed his girlfriend too before he came to their place.  This is from the late 2000’s I think and it used to be on Nteflix.