Hi, i had twin boys 10 months ago who were born at 31 weeks and after 3 months my periods returned to normal and where regular as clock work but the last few months they have been coming 2 and 3 weeks late and now i am staining between periods. I have also been getting some sharp pains in my lower abdomen nothing regular just here and there...could you please tell if this has anything to worry about..many thanks.