Cease all contact with her and do not send her any money. If you didn't read her emails, you wouldn't be stressed out. There is nothing she can or will really do to you. If she were truly in custody, she'd have no way to reach you at all. Prisoners are not allowed to have computer access or to keep mobile phones, This would have been confiscated as contraband.
It is not your responsibility to pay someone's bail, especially one whom you have never met personally. To send money -- and I'm sure she'd want it wired via Western Union or MoneyGram to a private individual rather than to the prison itself because the whole situation is a lie.
People who commit this kind of fraud are characteristically non-violent. They are interested in money and not in exposure. The possibility of her or her friends turning up on your doorstep to exact some kind of revenge is nil. But if you're fearful for your safety, block all contact and report her and anyone else who contacts you about her to your police. They will all stop bothering you as soon as they see they can't get money from you.
To repeat, she only has power over you if you keep allowing her to manipulate your feelings. WALK AWAY FROM THIS. This is not a real situation. It is a scam we hear over and over and over every day here. It will go away, as soon as you stop all communication.