Could I have passed a kidney stone and not felt it?

So a few weeks back I had a 6mm kidney stone stuck in my ureter. They got me in for emergency surgery where I had a stent fitted and I was scheduled for stone extraction and laser lithotripsy scheduled for today (4 weeks after the initial event).

However after the surgery today my doctor told me they went in with a camera and couldn’t find the stone. They think I may have passed it naturally. However I would have thought I would have felt a 6mm kidney stone coming out?

There was a few days where I had an intense pressure in my bladder and needed to wee all the time. I’ve also been drinking lots. Is it possible I could have passed it naturally without feeling it?

They have put another stent in me which will be removed in 3 weeks time.

Has anyone else had this experience?