Not your fault
Not her fault
You have tonnes of power
There is always hope
Her life is not your responsibility
No one can blame either of you
You are young
You don't sound healthy
Get the pain over with now as opposed to dragging it out. That is a shitty rollercoaster ride you are on.
High school did suck...and yes, this sounds like high school stuff.
This is a learning situation, not a lose lose one. Learn from this experience and find what you truly need to be happy. Maybe it's her, maybe not. From my perspective it's not her.
Sorry, my friend