My boyfriend is really good friends with my best friend?

He, lets call him "Joe", was friends w/ her, lets call her "Suze", before we started going out. I met him through her and we were the three musketeers in a sense until he asked me out 3 weeks ago. We are in 9th grade and "Joe" and I have lockers next to each other. "Suze" and I were the best of friends, and were inseperable. Now, its like I don't exist. I'll walk you through a typical day. First, we come to school. I'm at my locker when after chatting with "Joe" for a minute, "Suze" walks right by me and interrupts our convo to yak at "Joe" over their secret handshake, secret gang symbol, and mutual friends I don't know. Next, at lunch, "Joe" sits next to me and "Suze". "Suze" chats up "Joe" until I get so sick of hearing them I go outside. They follow me out and joke all recess. In math, they poke each other and mess around until the teacher comes in. After school, at my locker, "Suze" walks by w/o saying anything to me even tho I say hi to her. They walk 2 the busses together. HELP!