I've a low blood flow during my menses n it lasts for just 2-3 days.i hardly need to change my pad.moreover, i've excruciating pain on 1st day.?

Normal: Your situation doesn't seem to be outside of normal. If you have had this pattern since you started your menstrual history, it may be normal for you. A lot of times women who have had Mirena (levonorgestrel) iud or another form of Progesterone contraception such as depo-provera had shorter periods that don't return to their "normal" state after discontinuation. If that's the case, than that's ok as well.