If you are worried call your doctor or go to the er.
I am now spotting and dont know what to do?
I've experienced cramping my entire pregnancy so far and I'm 14wks, 5days. My doctor said it's normal and nothing to worry about unless there is bleeding. She attributed it to my uterus and ligaments stretching to make room for the baby and well as me not drinking enough fluids. Over the weeks it's happened more often and some days for hours, but the baby is doing well! So I just breathe through the cramps!
Period pain cramps are very common during first trimester just your uterus stretching. Like Ezzac said if you experiance heavy bleeding go get seen asap.
Alot of things moving around and implanting and changing at growing at 6 weeks. Don't get too worked up about it just yet. If the pain becomes severe or if you have any bleeding at all then call your doctor for a quick check up. I had cramps between 5 and 12 weeks for both my pregnancies and they have both been happy and healthy. :)