I had a lot of cramping in the early stages of my first pregnancy, I am only 5 weeks now and haven't had any cramping yet but am full expecting and prepared for it to start anytime
My girlfriend had bad cramps for a few days, they were crippling and she couldn't move for a few days. Honestly, I hear it's common when the pregnancy is starting up. Your body kicks into overdrive and starts growing and changing things all over.
I believe that bleeding is one of the key things to look for but if the pains are very bad go visit your doctor asap.
If it is really painful then I'd see the doc but cramping is normal so early. It's your uterus stretching and growing! If you aren't bleeding or anything then I would just sit back, relax and grow baby grow!!