I'm on my period and on 2nd and 3rd day night I've had pain in lower abdomen and anal part and feels like farts are trapped, there are 2 veins below the naval which feels are like paining. Usually I've never had any pain during periods this is happening from last time and this time only usually the flow used to be a lot which is not the case now( earlier I used to change 6 7 pads on 2nd day and now it must be 4 5) what could be the reasons for the pain and what can I do to avoid it