I had uncomfortable cramps in my first pregnancy very early on. You uterus is stretching to accommodate your growing baby. As long as you're not having any bleeding, there is no need for concern. It's all normal.
Its very common to have period like cramps in the beginning of pregnancy and even throughout as your body prepares itself to give birth if its concerning you call you drs office, theyll probably just suggest for you to drink some water and try and relax when the cramping occurs. I wouldnt be concerned about it unless the cramps are so awful you cant move or you start bleeding