Stress is a well-known trigger for depression and it can also affect your physical health. So it's important to identify the causes of stress in your life and try to minimise them. 
Any sort of loss, from bereavement, divorce and separation to a child leaving home, causes stress, as do long-term illness and disability. But things such as marriage, moving house, a new job and holidays have quite high stress ratings too. In work, worrying about deadlines or about not being up to the challenges of a particular task can cause stress.
Symptoms of stress : some common signs of too much stress include:
Increased irritability
Heightened sensitivity to criticism
Signs of tension, such as nail-biting
Difficulty getting to sleep and early morning waking
Drinking and smoking more
Indigestion / IBS
Loss of concentration
It's important to act to relieve damaging stress before it affects your physical or mental health.
The secret of managing stress is to look after yourself and, where possible, to remove some of the causes of stress. If you start to feel things are getting on top of you, give yourself some breathing space. Please see also CBT/H in the menu...