I can't fully relate... but this is the closest I can get to share:

I have very vivid dreams. I've definitely met people in those dreams, that I know are dream-people... but they were so real to me and often showed up in more than one dream. I care about those people and miss their company and get excited if they turn up in another dream again.

One of whom died in a dream years ago, as this dream-person had cancer. I miss him a lot and haven't seen him in a dream since.

So.. I would suggest not worrying about whether or not she was real. If naught else, she has been real to you, which makes her real.