Mama, please go to your OB or emergency room right away, lalo na with the hardness and that pain, hindi normal yan and baby might need checking urgently. Tungkol sa due date, your doctor lang ang makakasagot based sa which dating is more accurate para sa inyo, kaya important talaga na makita siya ngayon. A few of us had date differences din, pero the ultrasound is usually mas reliable, pero your OB will decide. Praying everything's okay, please don't wait, okay?