Increase physical activity by walking briskly daily for 30 minutes. This helps to improve blood circulation. Have warm foods like jaggery which are also a source of iron. If non-vegetarian, have meat and chicken preferrably with lots of black pepper which makes it spicy and increases body heat. Keep yourself warm and sleep well at night. Disturbed night sleep also causes irregular cycles. Stay active throughout the day and avoid worrying too much as it will increase stress. Hope this works for you.