What Causes Anal Pain During And Before Menstruation?

hello doctor, i ve a bulky uterus . i also suffer from breast pain throughout month but this pain decreases during my periods. since last 3 months i am also suffering from pain in my anal region. in the beginning i thought it piles or fissures,butwhen doctor examined its neither the two. he did blood test, x-ray and utra sound and found out that i am anaemic and i am loosing my blood.i usually feel more pain and contraction in my anal region before and during periods. please answer my querries. the gyn and surgeon gave some medicine now i am suffering from urine burn .thanks