Best friend?(rant)

Emma • Bi and proud🏳️‍🌈
So I am in grade 8. There is this girl whom I have known since I was born. Up until about 6 or 7 grade I would have called her my best friend, but now she's just kind of...drifted away. She is always hanging out with other people and she never says hi to me at school and can even be rude at times, but if we go somewhere by ourselves or we are at church(we go to the same one) she will act like she is my BFF for life, and will actually talk to me. Another problem is that she is very pretty and I have like no self confidance and I hate the way I look, so it makes me feel like she's ditching me because I'm ugly. I want to talk to her about this issue but I'm scared she'll get offended or mad and then I won't get her back as a best friend. I feel like if she's drifting away, then so should I, but I would miss her so much if we weren't "best friends" anymore. I really need advice.