Definitely not the same. I feel when you dream you feel some time has passed. I've lost consciousness a number of times for different reasons and the common feeling is it doesn't feel like any time has passed. One moment I was awake and the very next I'm on the ground, my head hurts and have no idea what is going on.. for the first 30 seconds I wouldn't be able to tell you my name, where I am, what I was doing, etc. Then it all just comes back after a minute or two and you realize what happened.
It's nothing like that. Your memory is wiped out, you don't know who you are, you don't know when you are. It's like you're in an alien world, nothing looks familiar. Your ears are kind of buzzing and ringing, your visual field is fucked up, etc. The last layers of your neural network aren't turned on yet. It's pretty weird.
...sounds exactly like waking up from a dream.
I think the more interesting point seems to be that the way you appear to wake from dreams is very different from 99.9% of people. For most people, waking from a dream is absolutely nothing like that.
Nope. I've also experienced this (just sort of fell to the floor unconscious and then woke up 10 seconds later). It was like my brain was slowly paging in bits of memory that had been stored out to tape. Like, who I am. Where I am. Why I am there?. When I wake up from most dreams, I have a bit of trouble remembering what's true and what's dream, but I know where I am, who I am, and why I'm there.
Do you regularly wake up extremely groggy and drained? That usually only happens to me if I am awoken mid-REM cycle. Perhaps that's worth investigating for you?