Am i losing my friends?

i have been friends with my friend britt for about 14 years and recently we have been distant. britt has been hangin out with my other friend la lately. it seems like whenever la is no around we talk and it seems like old times but, when la comes around those 2 are talking about stuff and i have no clue what they are talking about so i keep to myself. i dont know if i am losing her as a friend or what? what should i do to be close with her again? please dont be too mean. thanks!