depressed best friend): please help me

i honestly really need help. i'm watching my best friend fall into a deep dark hole of depression and she won't let me help her. she pushes me away and shuts me out. she even admitted she's been hiding things from me bc we've been so distant. she always makes excuses not to hang out with me and other people anymore. i'm so worried about her. she's not the same person that i called my best friend. i don't know what to say to her anymore, she often leaves me on read. i don't want to make the situation worse. she needs help, she just won't reach out for it, or take it when it's given to her. i'm currently typing this in tears as i try to hold myself together, i don't want to lose my best friend, and i don't want to reflect her depression onto me and make me fall back into it again either .