How can I support my friend with potential depression?

My friend has recently opened up to me and told me that some doctors think she might be depressed and I'm not sure how to best to support her.

Over the past few months, she had started acting differently and distantly. I had been planning on bringing it up to her whenever I next see her, partly to check if she is okay, and partly to let her know that some of the out of character things she said to me were hurtful. I don't think I'll mention that she hurt me anymore in light of her saying there's a potential she's depressed.

I have still tried to message her frequently throughout that and she would usually respond a day later with a very basic response and no effort to continue the conversation.

I'm just not sure how to go about things because I don't want to make things worse. I'm not sure if I should keep messaging her with random things since she doesn't really respond or if that could be making things worse and I should be taking a step back?

She doesn't really want to talk about it with me and I won't see her for a while since she's still away at uni and I just don't want to make things harder for her than it already is.

Any advice is greatly appreciated as I'm not really sure how to proceed