Where was she? Bathroom (it's a 4BR ranch house) and it's hard to get to the phone in 5 rings before the machine picks up (she still has a machine). Yard? The garbage has to go out. Still with my sister? That would piss me off, if my sister decided to run errands with my mom in the car, making her unable to honor her commitment to me.
The hospital. I was sure she was back in the hospital.
So I got angry at my sister so I called back and left a snotty message on my mom's machine because angry is easier for me to handle than terror.
I just have to stop worrying like this. Every time she doesn't answer, my mom isn't dying.