I'm going to go against thew grain here and suggest that the doctor won't be able to do much. In extreme cases I would always suggest seeking professional help. But in this instance it sounds like the problem is her job and I don't think the doctor can offer must assistance other than medication or counseling which will only be short term fixes here.
Resolving her job issue and love of life is the long term solution which isn't easy of course, especially in the times we find ourselves in. So short term while that issue can't be helped I would recommend a lot of physical activity like getting her down the gym which can really improve someones outlook.
Other people may expect more of us in our lives but our lives are ours to live and no-one elses.
This is by far the best advice here and pretty much what I was going to say. She is clearly an intelligent girl and probably gone through her accademic life being sold a vision of her future by her family her peers and the academic institutes she has attended. The reality of life once you leave this bubble as most of us know can be quite different and it is easy to feel cheated and sorry for yourself.
Here are two bits of advice I always find useful to think about whenever I get narcissistic:
Your life might not currently be the way you wanted or expected but you are also in a much better place than billions of people on this planet. Travelling to other countries really opens your eyes to this and is one of the best things you can do for your soul.
Thinking and worrying never achieved anything. It's only taking actions in the real world that ever make any difference. Never waste mental energy on anything that does not manifest something in the real world. If there is anything you can do then do it, don’t waste any time on the things you can’t.
Good luck give her your support and help motivate her and things will change for the better.