Did I handle this correctly?

I met a girl about a week ago online and we did allot of talking and gaming, we ended up really hitting it off and at the end of the night we cyber-ed, I was really enjoying being around her throughout the week and thought our relationship was going somewhere. Yesterday she hops into the chat and tells me she was contemplating suicide, then that she had just cut herself, I was worried sick and then an hour or so later she asks me what she is to me. I told her that she was my friend and I was worried about her. She said she felt crushed but I couldn't help but feel manipulated and emotionally blackmailed by the order of events, I felt like she was putting her life on my answer and she just kept pushing for one... I stayed up all night contemplating how to handle it and decided to end the relationship here... I am still worried my decision might effect her well being.

Yes, you handled it correctly. You were not cruel. You maintained your boundaries.

This wasn't a relationship, OP. You are correct that she is at most a friend, but this is clearly a very unstable and unhealthy person. How old are you both?

You were also wise to end communication with her. Do you know enough about her to alert emergency services in her area? If she tries to reach you again, tell her you will not hesitate to notify appropriate authorities who will help her.

I am 28 she is 24, no I don't and she cut all communication with me. I couldn't tell her why I ended it because I didn't want to fuel the fire so she is angry with me and feels led on. I do know someone that can pass the message along though. She said she is good now she just needed someone to talk to about it which she did last night, She said she has bi-polar mania and has that stuff happen sometimes and just needed someone to talk to. I still can't help but worry because she basically kicked me out of her chat crying and yelling today when I said I was no longer interested, which took allot of beating around the bush for fear of triggering her again, until she kept demanding a yes or no answer; I said no. She seemed calm until I finally gave her the flat out no.

been up all night, I'm really not running on all cylinders... and I can't help but feel like a villain here

I should have seen it coming

How could you have seen this coming? You barely know this person; it's not as though you knew what exactly what she is capable of (and you still don't)

You are most certainly not a villain. You are a man who made a very smart decision to not engage with this person any longer.