You might also want to look at the pages on this site related to out of hours or crisis support, bullying at work and the extra support available for recent graduates.  

• Mind, the leading mental health charity, offers the following guides to managing mental health problems at work:
  
  
  • Surviving working life
  • Staying in employment
    
    
• Royal College of Psychiatrists' Guide to Depression in the Workplace
  
  
• David Bartram's talk to RVC on The Science of Happiness