Shouldn't the nursing home have contacted me?

Yesterday, I tried to call my mom from 9 am to 3:30pm (if she didn't pick up by then I was going to call the nurse because sometimes she accidentally puts her phone on silent). At 3:30 she picked up and all she could say was "help help". I could tell her voice sounded strange, not frantic, almost calm. I called the nurse and she said she would check. My mom then called me back saying how she was in pain, but again her voice was different and she didn't sound in pain, then my mom said the nurse is here, and I got off the phone. Well then two hours pass and I get concerned again (my mom always calls me back). So I call my mom, she picks up and starts talking about how she doesn't know what's wrong, etc, etc, almost like she has dementia (which she doesn't, she is very mentally capable). I go on and ask questions and it turns out she was in bed all day and she said she had no drugs, but she wasn't in pain. I call my brother and sister, thinking maybe she had a stroke. My sister and I talk and decide to call the nurse. Turns out my mom had lots of pain meds at 5:30am that day and has been confused and in bed all day.... Now, at what point is the nursing home supposed to contact me? I thought I should be noticfied on changes in meds, as well as behavior changes. My mom was laying in bed confused and unsure what was going on all day by herself when it's not normal at all for her. She is always in her scooter doing something. By the time I found out it was too late for me to visit since I had to put my 3 little ones to bed. Not even including having the fear she had a stroke or something.