One of my friends keeps saying how suicidal shes feeling......?

i was at her house and there was a list on the back of her door with a bunch of tallies and i asked her what they ment and she reluncatntly told me they were how many suicidal thoughts shes had so far this year....when i told her she needed to get some serious help she tottallt flipped out and when i asked her what she would do if i told her mom (which im considering doing) but she said shed kill herself right away. i reallly wanna tell my mom but ik that shes just gonna lexure me about "being with people who bring you down and being in the wrong group" bc ive already been hospitalized for cutting and depression and suicidal thought/attempts and so has my best friend and when my mom found out she had too she flipped a **** and wont let me hang out with her (even though i do anyway shes my bestfriend i dgaf what anyone says im gonna hang out with her) but what do i do? if i tell anyone apperantly shes gonna kill her self as soon as i tell someone i keep trying ot get her help but shes refusing PLEASE HELP ME