Very old thread and op is probably past it for better or worse already. But I just wanted to say, all my school days were like that. So op is quite lucky that it happened to them only in the final years, and not from the very beginning.
However, struggling as I was, it did get better after I graduated. In adult life, relations with other people follow different rules and it's easier to get to know someone and be seen as part of the group.
Unfortunately, even if they do see me as such, I don't feel as such....for a very good reason.