What do you do when you're losing a friend?

Hey Reddit! I don't usually post much on this side of the platform, but I've been having trouble with a friend of mine. It's been happening ever since we got into college, and I'm scared to confront her about it. But for context, I have this high school friend who is really REALLY nice to people around her. She was fairly popular back in our old high school and she has a lot of friends, but somehow she ended up always accompanying me despite this. I don't know why she did it. I'm not really a social person, and I'm personally awkward. But she was basically my life support, and we were attached to the hip.

Thing is though, I've felt the distance since she grew close with her blockmates. Well this SPECIFIC blockmate of hers. It's as if they've become inseperable. Despite being in the same college and having similar-ish schedules, she's begun to ignore my texts and avoid me on campus. I don't think it's deliberate, but I've been sensing something bad about her blockmate. It's not just me too! Even her other blockmates are kind of iffy with the person.

Anyway, I'm kinda lost and I would really appreciate the advice. I don't want to lose my only friend, and I don't think it's just me being jealous. She's really really dear to me, and sure, she can have her other friends, but what about us? Anyway, that's all. Tips would really be appreciated