I'm having the same problem, my doctor says that it's normal to cramp it means that the baby And your belly is growing.
Drink some water and rest. They could be Braxton hicks. That's what they typically feel like is period cramps but not as intense. If they go away after rest and water, you should be fine. If they don't, call your dr. The first few Braxton hicks I got, my stomach didn't tighten, but they are starting to make my stomach tighten now because I have been getting them for about 10 weeks.