Nausea- headaches-dry heaves-cold extremities....medical tests fine...can it possibly be depression?

Anxiety. I understand your concerns. In the journey of life of 5o years, there are satisfactions and stresses. Stresses of marriage, separation, divorce, relationships, parenting, work, finances and medical illnesses can cause anxiety and depression. Nausea, headaches, dry heaves and cold extremities are likely due to Anxiety. See a therapist for Therapy, Breathing Relaxation, Visual Imagery, Tai Chi, Yoga.