My symptoms were similar to that, but not quite the same. I had a backache for 24 hours and then started feeling an occasional cramp. It was kind of like a menstrual cramp/digestive discomfort cramp. I thought I was just having usual pregnancy pains but didn't realize I was having contractions. In hindsight, I realized the pains were more and more regular and closer together.
If you're concerned, make note of the frequency of the pains. If they become more regular, go in to get checked again.