Depression and Post Traumatic Stress
Often, parents cope well during therapy, but suffer badly when it ends. Intense anxiety may erupt weeks or months after the crisis of treatment, attacking when you think you are coping well.
In medical terms, depression is a specific illness, not just a general “low mood”. Post-traumatic stress disorder (PTSD) is a distinct illness that can develop after a life-crisis like cancer. You may find it difficult to differentiate between them, and seeking medical advice is very important.