I think she realizes now and kind a did earlier (when she was resting against Tomo when walking when hanging out with her and Carol). That she is kind of dependent on Tomo as her only real friend and the only person she does anything social with. Her reliance on Tomo has been going on for 14 years now. I don't think it means she loves her. But I think she is really worried that the one thing she absolutely needs is going to become more distant to her.
seems like people in comment section were right about this girl (probably you have more experience with this type of manga). personally i always thought she was helping Tomo to get with Jun... if this girl interferes between them, things get even more annoying and slow, and i don't need yuri, so i'm out..