I don't know what to do anymore. suicide and best friends...?

my best friend in the entire world is ignoring me. one day we'll be talking and we're completely fine, getting along perfectly, laughing, etc. then the next day she full out ignores me. my other friend told me it's because she doesn't enjoy talking to me but i don't get it. i haven't said or done anything to upset her. i try texting, calling and facebook messaging her and she just ignores me. it's like she hates me for no reason at all? the last conversation i had with her we were talking about summer school and her sleeping over. the next day she just full out doesn't talk to me. i can't live without her, she's my best friend, blood couldn't bring us closer. i want to die, i've been researching suicide methods and i just downed half a bottle of extra strength neocitrin, i'm ready to die.