Frinships of 15 year olds

Ugggghhh my friends are the best I could ever ask for but there’s five of us in the group 2 of them are best friends and the other 2 are best friends then there’s me alone without a best friend who always gets left out.:( I love them but I love being left out and I don’t know what to do.i mean like they are nice to me I know I can talk to them about anything and I know they will listen and give honest advice but I just want a best friend to be partners with in class and I don’t wanna rush a friendship because I know that dosent end well and I feel lonely and sad and I want someone I can talk to about all this I but I can’t do this is why this website is so good