Is this it?!

For the past two days now I have been having contractions...mild contractions. I have been through this twice now (once without any pain relief) and I remember having these menstrual like cramps with my first two. I have three more weeks until my actual due date and Monday I'll have an ultrasound to check her measurements and see if I'm dilating. It's always at this point in the pregnancy that I feel extremely uncomfortable and am so ready to have the baby. I just feel so yuck right now....is it time?