Hard and tight tummy

Mae • Together since 10/2006 and Mom of 3. 11, 9 and 3 years old.....
My tummy is tight and very hard like rock. My hubby think not normal and he wanted to get check if it time to labor??? Never had this before from my last two pregnancy. I'm 38 weeks 3 days, and I have my dr appt on Tuesday. My dr hasn't check my cervix. I'm not sure what my dilated is.