Infertility and Mood disorder

Much of my work as a fertility counsellor involves supporting people who are struggling to conceive a child and are experiencing feelings of sadness, anxiety and distress.  These sorts of reactions are incredibly normal in the context of such a difficult situation, but when does this become a clinical problem?  This article from Infertility.about.doc explores the difference between feeling distressed by your infertility, and being depressed.