Cramps? Implantation?

Hey all! My husband and I are trying for baby #2, and this is our first month ttc but we had huge success with our 1st baby. I am supposed to start my period on Wednesday but a few days ago, I felt a cramp that would come and go on the left side of my pelvis. Any ideas? I've read a lot about implantation cramping but I wouldn't spot or bleed. Just confused!