I am 9 weeks pregnant currently, and during weeks 4-6 I had lots of cramping. Occasionally it was quite strong. It was almost exactly like period cramps, except instead of the waves getting worse and worse, they'd eventually subside. It is very normal. If you are cramping and bleeding, that is not good. You can call and ask your doctor, but if it's bad you can always take a tylenol or 2. Good luck, hang in there.