Nursing internship help?

I am a first-year trainee social worker (school-based training, no practical experience). I am currently doing a 6-week nursing internship and have been working in a retirement home since yesterday. Today I was thrown in at the deep end. My supervisor asked me to wash a client (wash intimate areas, move a client, etc.). I have never done anything like that before and hadn't learned it at school either. She simply left the room and left me alone with the elderly men. After about 5 minutes she came back in and asked if everything was okay. Then she saw that I hadn't done anything really because I just couldn't. Afterwards I had to go to the toilet with a woman with dementia; she had a bowel movement. I thought my supervisor would stay with me but she took off. Then I sat on the toilet with the woman with dementia alone without help and was supposed to clean her up. I couldn't manage it because she kept trying to get up because of her dementia. Then I ran into the hallway to look for help, even though I wasn't supposed to leave the woman alone because she might fall, but I was so overwhelmed. There was no one in the hallway either. Then I got into trouble because I couldn't get anything done, etc. She told me she expected me to be better tomorrow.

I don't know what to do. I'm completely overwhelmed because I haven't been trained. Is it even permissible to leave me alone as an assistant trainee (not a skilled trainee)? During my internship?