Of course you're jealous. You don't think it's right - what? That she's got more money than you now? That you're still struggling but she's not?
Do you want her to be as poor as you? Would you be happy if she had nothing, like you? Because that's not very nice.
If you were her friend, you'd be happy that she's not elbow deep in shit any more.
I'm sorry that you are. It's tough. But feeling like you want your friends to have nothing or you can't be friends with them will only turn you into a bitter, horrible person and you can and should be better than that.
She's in this situation because her marriage has broken down. Poor woman. Do you think that she flung out her husband so she could live it up on benefits? She's doing what she's got to do at this difficult time.
And fwiw, a lot of people do things like go out a lot, get a whole new wardrobe, etc when their marriage breaks down. It helps them to feel a bit better about themselves.
If you were her friend, you would be supporting her emotionally during this time, not resenting her for having more money than you.
If you don't want to be friends with her because you can't stand to see her have things that you can't afford, then walk away. But be honest with yourself about what you're feeling.