Early ultrasound set conception around dec 6. lmp nov18-ish. not really known. how likely i conceived from sex on nov 22?

Not likely.: Even if you're counting November 18-ish as the first day of your LMP, conception was very unlikely from sex on November 22. Early ultrasound is remarkably good at determining date of conception b/c it's very detailed and b/c the process is quite predictable. For now, you should rely on the December 6-ish date as the date of conception and the date you can use to estimate due date.