Passing away

My sweet baby girl is about to go I think
She is squirmy but also very limp, can’t use her legs, and is labored breathing.

What do I do for her rn? She doesn’t have other rats, her sister passed a little bit ago, and I just don’t know how to help her through this. I’ve had her on my stomach and have been stroking her but I don’t know what is the right thing to do. Please please help