Hello, I have gone through your query and understood the concern. If the cause of your weight loss is not known, get the help of a specialist to know the cause. Hormone assays are needed and so is a sonogram of the pelvis, preferably in the trans-vaginal route. Your present menstrual picture depicts hormonal imbalance. Appropriate supplements can be given once the causative hormone defect is known. Infections, stress, certain medications are other known causes. A few courses of hormones will help to settle the issue if other causes are excluded. Hope this helps.