Oo normal yan, girl! Mine was like that din the whole pregnancy, sometimes soft, sometimes hard, lalo na pag nagmove baby or pag nag-stretch uterus mo, ganun talaga ang feeling. A few of us in our mom group had the same worry at 18 weeks, and our OBs said it's totally fine as long as walang severe pain or bleeding. Pero kung gusto mo talaga ng peace of mind, might as well ask your doctor sa next checkup, walang masama sa pag-check lang, kaya mo yan!