Wrong due date??? Shes dropped and the pressure is on??!!...

I was never 100% on sure what day or week I conceived because I had just stopped taking my birth control. Today I am 33 weeks and 1 day according to my due date the doctor gave me. The baby has dropped. Even my mom who I visit everyday said the same. The pressure in my crotch is so bad that I had to AIT in a warm tub just hoping for relief. Could it be my due date is off by more then a week or two or is all of this normal at 33 weeks??