Tmi, sorry!

Meadow
I'm sorry this is kinda tmi
But is it normal to have so much pressure during your period that you can't poop? Like, my lower back is hurting along with horrible cramps that make me sick, and I can't poop along with that. 
Is this a normal thing or should I be worried? I have fiber in my diet and I stay hydrated. I normally poop like 3 times a day.