Signs of depression in close female friend?

I really don't know how to help her but I really want to because I know she has good in her because she has helped me through depression and has always been there for me. We've been friends for a long time and she finally told me that she's a horrible person and I could do better. I asked her why and she then told me "I've become less tolerant and I talk badly about almost everybody" So I then went into how I was not going to give up on her and that I can help her change and she then told me "Hating is easy for me & I don't care. I don't care about changing and I prob won't be able to. It's just how I'm wired. I literally have hated people since I was little and just talking s*** about them and being annoyed really easily". She has always managed to hide this from me. She then told me that she doesn't hate me but she hates a lot of the thing I do. I really want to try to help her but I don't know how. She's really a sweet person deep down. I feel like that what's she's saying isn't the full truth because I don't understand how anybody can be happy like this. She told me as a kid she used to mouth off to the teachers etc. but she no longer does that. One other thing about her is that she's fairly antisocial and prefers texting/skypeing/calling to communicate with the few friends she has. Also to give you an idea of some of the things that annoy her I copied and pasted this. ''Oh btw another way not to annoy me is don't ask "what's up" because I hate that question so instead of asking that, just talk about random stuff idc
Like if you don't know what to say and all you wanna say is "what's up?" Just think of somethin else to talk about idk. It just makes me mad for some reason" I just wonder if these are signs of depression or something else cause I don't know why she's like this.

Could be depression, could be just anger. Is she anger about something else in her life and taking it out on you? sounds like she trying to push you away. Best thing to do is not to react and let it pass. Then in the hindsight she may be able to explain further?

Well things are a little better now and I know she isn't trying push me away cause it's been over a year since we've been friends and I know she isn't a user cause we help each other 50/50. She's kinda like this with everybody really apparently and she often vents out her anger about other people to me. like She'll complain about em a bit etc. She told me she feels bad about it but she can't really change it. You may ask why I'm still friends with her? Well she's done so much for me and I know she has lots of good in her, but I just have a feeling she may not know how to deal with frustration and anger. I feel like there's a deeper reason for her behavior, and although she basically says that she doesn't care if she hurts the people she hates. I just think(I know) she gets annoyed very easily at people, so in her annoyed state she says things she really doesn't mean. That's kinda what I'm thinking. I almost think she kind of enjoys being angry sometimes, but since she doesn't get angry at me very often I myself can deal with it, but I don't know how to help her.