Mine has been doing that as well, flopping every time he goes to sleep but he's healthy and is doing just fine. That just means they're comfortable and you're doing everything right but if they start to flop when they're standing or seems unsteady on their feet I say take them to the vet to get checked out for underlying health issues.
Since the "dead bunny" flop, or just flop, is a very vulnerable position for these precious prey animals, the fact that your bunny is flopping almost all the time is a sign of trust. Also, try uploading the video to youtube and then linking it.
Usually when they are just laying down and pop back up when disturbed and then act normally, this is just them being content and relaxing, but there are a few types of flops that can indicate a health problem.
https://wabbitwiki.com/wiki/Understanding_your_rabbit http://language.rabbitspeak.com/
Flaccid and lethargic flopping where they have very little or no control of their body and can't usually get up or even move. If they are still mentally alert, this can be due to floppy bunny syndrome. Not alert or not conscious, this is other serious health issues, often fatal ones.
http://wabbitwiki.com/wiki/Paresis_and_paralysis
Then there is flopping where they are belly pressing due to their stomach hurting, usually with their butt somewhat pushed up, and their front end may also be somewhat up. They often will also seem restless and keep changing position. They may also be tooth grinding.