I'm still getting random cramps at 9 weeks- especially when I have to pee ('cause I think I'm running out of room).
At 8 weeks I talked to a nurse educator and 2 ob's about my cramps (worse when dehydrated, even with the slightest bit of exercise/stress, coughing/sneezing, and standing up / stretching quickly)- they said it's totally normal, and just because my uterus has never been this size before. I've had them since 3.5 weeks!
I think the big thing is as long as there's no spotting!