I can just just barely feel a hardening uterus, but I also know where to feel - I have my c-section scar as a guide.
For those not feeling symptoms, try not to worry. I had ZERO symptoms with my son. None. It was magical. This time around, I'm as sick as a dog, and I'm not enjoying my pregnancy as much yet. So, try to enjoy. When your baby is in your arms, you'll regret the constant worry and stress over symptoms, I promise.