my doctor gave me two due dates the first was nov 21 and the second was dec 5.whitch one should I go by

I have 2 as well. I just go by the later one. Usually by now they should be more certain by the growth of the baby.

yeah I only had one ultrasound I don't know why

Usually the second one tends to be more accurate. I'm due the 27th. Weird that you've only had one ultrasound though!! 🙀