Friends are leaving me out?

I met these girls last year and we instantly became friends, but they always had the most fun together. They always said how it would be so fun if WE did this together or I could totally see US doing this. And ive just dealt with that.One day I told them about it and they said they didnt realize and theyll never do it again. It stopped for a while and now its completely obvious. Now we are hanging out with some more people from school and one girl is totally changing one of my main best friends. Also on facebook my friend who I thought was my really good friend (A) tagged (N)as her best friend and she tagged me as animal lover. Then she tagged all of our friends on something else but not me. Also, she has totally lied to my face. Just now she called (N) to see if they could hang out. She said she couldnt and then she had to leave my house. (we werent leaving (A) out this was right after school and (N)needed a ride home) Later I called her back and I asked her if we could hang out, I think she doesnt want to hang out because she said she couldnt. Any suggestions?