Firstly, we cannot help diagnose. Secondly, unless you are trained (which I guess not since you are asking us for help with it) you shouldn't be trying to diagnose either.

It is not worth trying to diagnose your friend, it'll only cause hurt to you both and not solve the problems anyway.

Your last question is more important in my mind- how you can help.

You can support your friend in seeing professionals for a diagnosis/treatment/help with her problems. You can also be a listening ear for her. You can help her practically if she needs it. However if she does not want to seek help it may be hard for you to get anywhere in the treatment way of things. But being a friend and giving space and time for her will be the best thing you can offer. It sounds like you really care, hence making this post, and showing how much you care would probably really help her.