Barb,
The exact cause of depression is unknown. It may be due to deficiency of a brain chemical called serotonin or other so-called "neurotransmitters", genetic factors, medical conditions, or other stressful events. Your post suggests a combination of physical and emotional causes of your depression. Product information states that Plendil and Atenolol may cause depression. Depression is treatable by a combination of medications and psychotherapy. I urge you to seek medication evaluation with a psychiatrist, and to discuss your concerns about antihypertensive medications further with your treating physician/endocrinologist.