I had no symptoms until 7 weeks. Some women never have morning sickness either. About the boobs, it depends on the woman, you might notice a change in color (more veins showing) or the nipple being darker. But it happens at different times for everyone. Your cramping is a symptom and it is normal as everything is streching to make room for the baby. Relax, go and see a doctor to confirm it. You are ok!