Sorry if I offended.. but I really think it's a matter for professionals. You're in a situation similar to what my friends and family went through when I was freaking out. They couldn't do anything for me.
She needs to choose for herself someone she's comfortable confiding in. She should look for ways to reduce or eliminate stresses in her life, and as she feels ready - she should make sure she's getting plenty of sunshine, exercise, and eating a healthy diet. Panic attacks can come from a feeling of 'not being in control' - so you forcing her to get more sunshine, exercise, etc. may not be helpful - she's still not in control.
Preferably she would see someone who can evalutate her neurological and neurochemical state in addition to providing phycological support. Panic attacks can involve an imbalance of neurotransmitters - which in turn can be caused by or causing a variety of things including hypo- or hyperthyroidism.
It's a matter for professionals, and can take time (up to a year or more) for the body to return to a normal non-paniced state. The idea to get medical help should be her idea - but you could suggest it if you do so in a way that doesn't put her on the defensive. (For example, best not to ask "Why don't you see a professional?")
- Lime