Painful occasional cramping early in pregnancy

Tracy • Married❤ we are both 26 and we found out we are pregnant with our first baby September 22nd 2014!
I'm 6 weeks pregnant and I'm getting pretty painful cramps at times. It feels almost like I have to use the bathroom but nothing happens. I'm not bleeding so no miscarriage but I'm wondering if it will ever stop? Is this normal? I've been cramping for 3 weeks now.