I hate that I feel the need to tell my mother that I can't handle her when she's off her meds
Why do you think that you need to tell her that?
She causes so many problems without them that I want to scream it as loud as I can.
I think that some meds are important. If these are meds that drastically change her behavior, I can see why you would want to tell her to stay on them.
I hate how much anxiety she gets and my father is worrying all the time. She's driving me mad and the kids. She drives me to the point where I want her dead sometimes.
It's not a super comfortable position to be in, but you're right about needing to tell her. She probably doesn't realize how much they affect her, so being honest with her will only help her. It'll be worth it when she levels out again and everyone can feel at peace.