To [B]Joanna63[/B]: Yes, it could very well be and that’s why I’m letting it rest.
To [B]InnerAthlete[/B]: Woa! Hold it, wait a minute… Do you know that you can be a little scary at times? You make me feel like I’m taking a test here, but that’s probably a good thing.

OK, the Iyengar book was mentioned because instead of finding a picture on the internet of the pose (like you did) I thought of a book that I was sure you also have. So, Iyengar is not really a source for what my yoga practice looks like and I tried that bridge pose about six months ago just out of curiousity and at the time it had very little to do with yoga. It was part of someone’s work-out routine and supposedly very good for any neck or back problem. I tried it, felt the pain and gave it up… and perhaps slowly started to make the connection between how that made my neck feel and how headstand has had a tendency to make my neck feel.
Anyway, the thing here was that I wasn’t bearing any weight on my head sicne I wasn’t doing matsyasana the ordinary way but used a ball (small plastic ball, a little smaller and softer than a regular one used for soccer) placed between my shoulderblades and my neck, creating the backbend but with the back fairly passive and without the head touching the floor.
What level is my yoga practice at? Pretty basic and confused I guess. I should probably go to a yoga teacher (I know you won’t disagree with me on that one). I did go to yoga classes long ago (we’re talking over 20 years ago), at Satyananda yoga center in my home town (Uppsala, near Stockholm). What I do today is a mix of what I remember from that and whatever I have picked up on the way and whatever I want to try.
While nobody really told me to bear my weight on my head and neck after sarvangasana I was taught to do matsyasana after sarvangasana, as a counter pose. These days I think that I’ve never been able to do the fish pose correctly but back then none of my teacher reacted to it. Now I try to just go as far back as I can without letting go of the arch in the back, without collapsing as you describe it, which I think is what I’ve been doing all these years, just leaned back and then lifted it all back up again with my head.