Please just hold on.

It's not worth killing yourself over this. Know that whether she is alive or not, she would definitely not want you to commit suicide just to be with her again or to punish yourself all of this. No, just the opposite. She'd want you to keep your head held high and carry on for life, as much for you as for her. Think of your bestie and all of the people that obviously do care about you. Put yourself in their shoes. Would they like it if you committed suicide? Definitely not, and neither would your worst enemies wish that on you. It's not worth it.
I'm sorry that I have to go now, I really am, and I really DO want to hear from you tomorrow because you CAN get help. Call a hotline or talk it through with someone or even go to the hospital.