[hocus pocus]

I can understand that fear. When you've been abused there can sometimes be a part of yourself that logically knows things, and there can be a part of yourself that returns to the event and that part of yourself needs to be comforted. So, even though you know that the chances of something happening are slim, you have emotion tied to the last trip and that emotion is making it hard for you to go on this trip. You said you don't want to tell the school because you don't want anyone to ask questions. If you wanted to, you could tell them indirectly. You could always tell them that you had a bad experience and struggle with sleeping next to someone.

I think you should bring things that comfort you. Maybe a pillow or a certain kind of lotion or any other object that makes you feel at ease. You could make a small list of things to do before you fall asleep to help you feel safe, too. While you're there, try to remind yourself of your surroundings. Let yourself know that you're in the present and you are safe.

I hope the trip goes well.