Chronic Illness

It is common to feel sad or discouraged after a heart attack, a cancer diagnosis, or if you are trying to manage a chronic condition like pain. You may be facing new limits on what you can do and feel anxious about treatment outcomes and the future. It may be hard to adapt to a new reality and to cope with the changes and ongoing treatment that come with the diagnosis. Your favorite activities, like hiking or gardening, may be harder to do.
Temporary feelings of sadness are expected, but if these and other symptoms last longer than a couple of weeks, you may have depression. Depression affects your ability to carry on with daily life and to enjoy work, leisure, friends, and family. The health effects of depression go beyond mood
It is important to not dismiss depression as a normal part of having a chronic illness. Effective treatment for depression is available and can help even if you have another medical illness or condition. If you or a loved one think you have depression, it is often a good idea to consult with a mental health provider.

https://www.nimh.nih.gov/health/topics/depression/index.shtml#part_145398