progesterone shots and cramps??

Hi Ladies, 

I'm 6 weeks, 3 days along and have noticed that two times now I've started cramping after taking my progesterone shots.  I know it's only two times but my dose had recently been increased as well. My doc kept my higher dose because he said the progesterone can relax the muscles and ease cramping. Just wondering if any of you have experienced this. 

Thanks