Did shopping and paid, but went back several hours later and did the same but did not remember the first time is this common with depression/low weigh?

Memory loss can: be caused by many different things. Depression is one, but the degree of your memory loss is concerning. Please see your doctor. He/she may suggest a neurologist and maybe later a neuropsychological exam depending on results. Peace and good health.

Depression: Occasionally short-term memory disturbances can factor into depression. Get checked out by your primary care physician to rule out any physiological cause for what bothers you. Ask for a referral to a reputable psychotherapist for depression.