I'm scared to go to high school..?

im litterally terrified of highschool, ive been looking at articles on the computer and all, but they usually go with the elementary then middle school then highschool thing but, i live in montreal and go form elementary to highschool for grade 7! im completely terrified! my friends are in french immersion and im in english immersion, we arent in the same classes (not sure yet, but im pretty certain) there is also the stress to fit in and be popular, the stress of knowing your way around the school, the stress of being to fat and look weird and uncomfortable in your school uniform, i tend not to study and slack off in elementary and do some homework in the bus and not learn my oral presentations by heart and ect ect! please help me! i need advice about how high school will be!