Cramps

Hi, ladies! Does anyone else experience consistent period-like cramps? I've been having them for the past few days. I'm 13+3. I asked my doctor about it yesterday, and he said as long as they weren't severe, there weren't any contractions, and there was no bleeding, it was normal. But I'm still worried. I think today's cramps were brought on by physical exertion. I was helping move some tables that were on wheels, and afterwards I felt the cramps. Now I'm worried I'm miscarrying. Help!