Freaking out!

Okay here goes. I went in for my 36 week appt on tuesday now 36w6d and was told my baby is already measuring at 40 weeks and that she could come at any time. I was only 1 cm dialated. Last night while trying to sleep I could feel my babies head every time I layed my legs on top of each other and it burned! This has continued all throughout the day in whatever position I am in. I have also been cramping, and having some serious back aches. My stomach has also been tightening, but it hasn't been very painful so I wasn't to worried. My mother kept texting me and asking me if I had diahrrea or anything. I thought she was crazy. Well lo and behold just a short time ago I literally sat on the potty for a full 5 minutes. I couldn't stop it from coming out.(which resulted in my first hemroid. I'm not to pleased about it😠) Anyways did any of you ladies have similar symptoms that were the start of labor? I'm a FTM and I've been freaking out all day.