Mom doesn't recognize a picture of my older sister and brother,she thinks its her and my uncle. Could it be the Cymbalta?

In the past it has been an infection, or a medication problem when anything like this has happened. Lorazepam. It almost did her in. They did a urine test on Thurs. no infection. She is argumentative. And, so sure she is right about things that she is obviously wrong about. She does everything but calls me a liar. I realize there is nothing I can do but let it go. I can no longer trust what she tells me. I have no idea if she knows what she is talking about? What can I possibly say to someone who can not recognize a picture of themselves or someone else? She has not been diagnosed with Alzheimer's or anything of the kind.
My oldest son has mental problems. Sometimes he is so nasty I feel like I can hardly stand to face the day? Between the two of them, and a very demanding
spouse OMG... I sometimes want to just stay in bed, run away or something!
thanks for listening.