How can I stop freaking out? (check details)

So school is starting in a month and I’m going to a really big school and I’m freaking out here!! I’m worried about going to school again because I think I’m going to forget my locker combination and get lost on the first day and there are people there that are like WAY bigger than me and I think I’m gonna get made fun of which I dont want to happen and everyone keeps saying that it will be ok and I don’t really know if that’s true and I’m just really worried and I don’t know how to stop freaking out every day :P