Unsafe Behaviors

I am a teacher in an early pre-k classroom (mostly three year olds). I have had some children move into my classroom recently that have some tendencies and it’s hard for me to handle them. I have one child, a girl, who constantly runs or doesn’t come with us at all when we are going from room to room. It is especially bad when she is told she can’t do something (i.e. be line leader or caboose). I know it may sound bizarre but she will just run away from us when she is told no. If she doesn’t run she just sits where she’s standing and does not follow. This is extremely stressful for me because obviously I want to be able to see her at all times just as I do the other children and I don’t want any of them left behind. This is exacerbated whenever I am by myself and unable to walk away from the children who are listening & in line to go grab her when she runs off or doesn’t follow us. I also have a boy (who has an autism diagnosis) who will not keep his hands off of the other children. He hits, pushes, kicks, etc. I do not believe he understands he is hurting children, but he obviously is and it is becoming an issue. Children are going home with bruises and marks and parents are asking questions. My admin is little to no help with either of these issues and honestly they make me feel silly for asking for help. Not all of the time but most of the time and it is honestly infuriating. I feel like I am becoming burnt out and I also feel like I have a short fuse with my kids at work now and I hate that. I love them very much and I love my job but I feel like all I do at work now is yell. Does anyone have any experience with extremely frustrating behaviors and admin that does not help you? Any advice is appreciated. Thank you.