Who has ever lost their 'closest' friends?

I have a friend that I’ve known since I was 12, and I’m almost going to be sixteen now. It was me and brenda, and then sophia joined in in 9th grade. Since then, we were all extremely close. Except we got into that phase where we’re so close to one another we forget how mean we can be at some times. Well, that’s what happened! It was a slow process, sophia & brenda made everyone else feel like the third wheel. Randomly, sophia would just pull the cold shoulder and invite only brenda to places in front of me. I remember once I was at the mall with them and I was in the middle and I was talking, and sophia pushed me out and said, “I want to be in the middle.” I guess she realized what she did and said, “well, it’s because you’re so much smaller that I feel weird next to you.” so I just moved to the other side. It’s as if they’re in love with one another and it really makes me feel excluded at times. I don’t need all the attention but I feel like they’re not the right friends for me anymore. If I do this, I won’t have any friends at my school anymore. I don’t know if it’s the right thing to do. Maybe I’m being to dramatic, lol. What do you think?