40 weeks and lots of pressure in rectum?

first of all i have not been able to stay off of the toilet going #2 for the past few days now. Im pretty sure i am having irregular contractions also. I just feel tightening at the top of my uterus and some get a little more intense and move lower. Every time i feel like i am having a contraction i feel tons of pressure in my rectum. could this be a sign of labor? or what could it be?