Wow this hit really hard for me. I had a similar experience in middle school just being alone since I was that weird guy, but didn't know it untill sophomore year. I know the feeling of being the ghost, that no one knew my name and hearing the teachers say group up was terrible. I never had lunch, I just did the same thing read a book or walk around. Thankfully I became social and had made friends in highscool.

But telling your bf what you wanted to say seems like it could help, why do you think he would see you differently?

Trust me you will be fine, but you need to be honest with your self and the people around you. I can speak from experience that things will get better, but you need to do something to make things better.