>>1There are two types of suicidal people.
The first is one who is serious about committing suicide, the one who does it without a second thought without telling anyone. These are the people who are really in trouble, who need help as soon as possible.
Then there's the second group, which your friend fits into. This group is the section of people who are really more into it for the attention. This doesn't mean that they AREN'T suicidal, rather, that they want people to pay attention to them and help them out of the rut they think they're in. These are the people who always tell someone they're going to do it, when they usually come up short. These are the people who will post their suicidal thoughts on facebook or twitter.
Luckily that means that she's in the group that doesn't really want to commit suicide, you've got a better chance at making sure she doesn't do anything irrational. Now, from here, there's two main options to take. Keep in mind that there's always alternatives.
1) Give her the attention she needs. Start giving her the attention she wants, trying to make sure she feels needed. A good way to do this would be to give her some small gift, and go with her outdoors and do things in the city. Perhaps even a theme park, or a simple walk in a park.
2) Now, this is by far the more aggressive method, but can be effective if the person is isn't really suicidal, and is mostly in it for the attention.
Snap her out of it.
I've seen people who've had their friends murdered on holidays as a child, and they've still made it out ok. There's people who live off nothing but what makes it to trash cans, and still manage to get by. If she thinks she's got it bad, she's nowhere close. Keep in mind when walking through the city you could show her examples of this. Basically the idea is to show her what she should be grateful for.
Pick an option, put your own spin on it, and give it a shot. Best of luck, OP.