38w2d getting so frustrated

When I was pregnant with my twin daughters, I dilated and went into labor naturally at 37w5d. Now I'm 38 weeks and I'm not effaced or dilating at all! The doctor said my cervix is very soft and she can feel his head but that's it. I feel like I'm going to be pregnant forever and I don't know why this time around, my body hasn't stated dilating or effacing!