I am so sorry to hear that your daughter is suffering.
Has she explored any self help routes as yet, or spoken to the GP who can sometimes offer extra support, such as counselling services or Cognitive behavioural therapy (which can help address unwanted thoughts) etc?
NLP or Life coaching are other techniques used to help individuals tap into their own inner resources and find new ways to overcome challenging situations.
Both are helpful as they work to empower the individual which in turn can boost self confidence.
When looking for a practitioner I would recommend an online search for 'NLP or coaching accreditation bodies' to ensure professional training standards have been achieved.
There is not, as yet, one central organisation with whom practitioners can register, so it is worth exploring and also seeking recommendation via friends or family.
She may also find it helpful to try Passiflora complex, traditionally used for easing stress and nervous tension. It takes up to a week to feel the benefits and if she has not noticed an improvement after a month, then we suggest exploring an alternative.
Confidence Essence may also be worth considering as it can help improve emotional well-being where issues of self confidence have been a problem.
I do hope things improve soon and your daughter finds the best course of action to help her.