The Broken Promise

I have a friend at my school. I’ve knew her since sometime in elementary schools, but we’ve only become rather good friends only this year. i feel comfortale telling her thoughts about my life since she also has a lot going on with her family and has counseled many people before me. once in math class many months ago, as i was thinking about life and such, i told her i thought that i was suicidal, though not as seriously suicidal as i am now. since she did not respond, i assumed she didn’t hear me. then, after school, she asked me if i really felt i was suicidal. i said that i guess i was not, and she made me romise to tell her if i’m suicidal. months have passed, and i feel the situation and desire has gotten worse.  don’t feel as if i care about anyone except  myself too deeply, but i feel badly lying to her in this way, so directly. of course i don’t think i should actually tell her, who knows what would happen then. but i do have a friend, who i’ve told my suicidal urges to since she is suicidal as well, that i may be able to give a messenge to in case i do commit suicide. i would tell her to be very cautious because there may be a slim chance that she won’t know i commited suicide at all. i would ask her to say something on the lines of, ” i’m sorry that  broke my promise to you.” that is all i feel i owe her. but, my suicidal friend may not really be serious about suicide, or not want me to commit suicide because i am her friend. once, while i was telling her about ways i would like to die, she retty much killed the whole conversation by asking ” you aren’t really suicidal, are you?” then we had a minor arguement until one of our other friends  came up to talk to us. i not exactly sure what i should do, so it will be very helpful if i could some advice from you all.