Of course, so could other things, but the group of findings you've listed shouts endocrine cause. I'd get to a doctor who will check hormone levels. An endocrinologist would be your best bet for a specialist. Treatment, if thyroid function is found to be lacking, is pills. Usually, most of the problems such as weight gain, fatigue, hair falling out etc resolve in time.
Memory loss can take many forms and be from many problems.
Most of us are afflicted with occasional short-term memory loss when busy or distracted. While this isn't a disease, with some concentration and association tricks, these problems can be reduced. These can be signs of various brain or metabolic problems. Common diseases or conditions affecting memory include changes from excessive alcohol or drug use, progressive dementias and Alzheimer's disease, strokes, and brain injury. Signs of memory loss should prompt a thorough evaluation.