Hi, I Was Having Cryptic Pregnancy For The First Month.

Hi, I was having Cryptic pregnancy for the first month. All pregnancy test and ultrasound turn out to be negative. After a month, my gynea told me that the test was finally positive. My LMP was 10 Apr 2015; EDD should be 15 Jan 2016. But later my gynea gave me a new EDD base on the size of baby during ultrasound which is on 8 FEB 2016. In another word I'm currently entering the 32nd week of my pregnancy. However I got admitted to hospital due to virginal bleeding. My gynea gave me two steroids jab for maturing my baby's lungs. Contractions came non stop and I was on bricanyl to cut down on the contraction. Doctor is doing whatever he can to delay my delivery. My question is could my due date be wrong?