From the history given by you, we could think it can be due to postpartum thyroiditis. Postpartum thyroiditis is a painless inflammation of the thyroid gland that can occur in the mother usually within the first year after delivery, usually from eight weeks to twelve months after childbirth. The signs and symptoms vary from woman to woman. The hair loss after pregnancy is very common and it is a compensation for the hair gain during pregnancy. The initial experience of signs and symptoms of overactive thyroid or hyperthyroidism, which may include rapid heartbeat, sudden and unexplained weight loss, nervousness, fatigue and increased sensitivity to heat. Later, you may develop signs and symptoms of under active thyroid or hypothyroidism, which may include unexplained weight gain, hoarse voice, irregular periods, constipation, puffy face, fatigue and increased sensitivity to cold. Typically, the symptoms are mild. In fact, they can be so mild, that many women are unaware that they exist or dismiss them as a normal part of having a baby. The cause of this uncommon condition isn't known. In most cases, thyroid function returns to normal within 12 to 18 months after onset of symptoms. However, some women develop long-term hypothyroidism and need lifelong thyroid hormone replacement therapy. The other common cause could be Postpartum blues with depressive symptoms and signs. Since you are coping up with the play of your children. It is not worrisome. Next step in your case would be to consult an endocrinologist for further evaluation and treatment.