Pain during periods. During menses?

I delivered my baby 5 months ago and I have been getting my periods regularly since 4 months as I'm not breastfeeding her exclusively. Everytime I have been experiencing heavy bleeding on day 2 and 3 and then it gets completely over by day 5 with only spotting on day 4 and 5. On day 2, when I bleed heavily I feel slight pain and pressure on my vagina and anus as well, especially while standing. I was also diagnosed with anal fissure just a month after my delivery which was treated but I'm still consuming fibre rich foods with hell lots of water and practicing hygienic bowel movements. I want to know that is it normal to experience this slight pressure and pain in vagina and anus on second day of menstruation?do fissure or anal muscle spasm gets triggered during menses?