I am putting on weight, for no reason, I am not pregnant, nor eating more, I find myself more active. I have 2 children aged 5 and 3.?

Must solve a mystery. When a person "gains weight" for "no reason", the real reason must be found to decide if there is a medical problem going on. The doctor can help find out if there is an endocrine (hormonal) problem, a kidney or heart problem (causes water retention), or a tumor (abdominal tumors can be big & heavy). If no disease is found, then the person is simply needing fewer calories than he or she is eating!
Change in BMR. Basal metabolic rate declines with increasing age and would result in weight gain unless you reduce your caloric intake from when you were younger.