My Father was in rare form last night.

My father has Alzheimer's. Last night he was really off. He was talking about things I had never heard before from killing himself to how I should leave him and get out of the house. He was very antagonistic towards me, insulting me and treating me with no respect at all. He had never acted like this before. Frustrated and maybe a little sharp but never really mean to me.
It was very upsetting even tho I know he has dementia and can't be responsible for what he is saying it still hurts to have your father treat you this badly. I regrettably got so anxious that I yelled at him while having a panic attack. He won't remember it but I do and I feel badly about it.
I don't know how much longer I can take this.