What should I do?

I think she might be having mild depression. or if she's not, i'm scared that she will be someday.

I can tell she's under a huge amount of stress.
I can tell she's roaming in circles, not finding a way out.
I know she doesn't like to tell people what she's really thinking about.
I know she has difficulty trusting people.
I know she fears rejection.

I know she's locking herself in her own world, not letting people in.
But she just opened a small door for me.
She's asking for understanding.
She's asking for a listening ear.
She's asking for a friend.

But with her stress level and how she's managing it, I'm afraid I'm not competent enough to help her through it.
But how can I tell her to go for stress management course?

What should I do?