My best friend has a new best friend?

My best friend just moved to the other side of the country. It was so hard to see her go and I miss her so much. I'm 13 and I've known her pretty much forever. I tell her everything and we were best friends! But now that she moved she has a new best friend. Someone who is more like her. We both promised to stay best friends after she moved... but that's not happening. Like on instagram she posts stuff of this new friend and says that they're best friends. I miss her and love her is a friend way so much. Another thing is that I am going to a new school. All the people at this school I'm going to already have best friends since they've been there for a long time. I have a lot of friends, but no best friend. I feel so lonely and I miss my old bff so much :'( Any advice? I haven't really talked to my friend that moved about how I feel, but I don't really want to. Thank you! And sorry if I'm being dramatic but it just sucks so much ugh