No professional advice from me, not even some godd advice, just what I was longing for in my own bad times:

Simply don't leave her(/him)! Sounds cheap, but it is extremely difficult to really do so. Take her in your arms and hold her (be careful when you do it physically!!! - if she's female she might take it as the opposite, if he's male...) Never ever give her the least impression that you want to get rid of her (e.g. to a doctor - ouch! - I don't want to say that a doctor is bad, the problem is telling it to her without - my dictionary says: 'repudiate' - her in her view). Be 'strong', and from that position of strength tell her that she's still all right. At least beware of the opposite.

Good luck

Joerg