I came home from lunch to find him unresponsive. Rushed him to the vet, had them try to resuscitate. He was only 2 1/2 years old.
I have a camera set up to watch both of my bunnies, and it captured what happened. I don’t understand though. He’s fine one minute munching his hay on top of his litter, then he stops, kind of rocks forward and back once, then freaks out and tries to run the opposite direction he’s facing, but falls.
He then cranes his neck way up high, while on his stomach. Then relaxes and jerks a few times over the next minute.
I get there 43 minutes later.
Vet thinks maybe seizure or heart attack. I don’t understand how this can just happen. I’m destroyed right now, me and my gf both. He was part of our bunny family, because that’s all we really got. 
Here’s a pick of him and snuggles.
https://drive.google.com/file/d/1xSqs_86akWqSck8osJpp-JXedxx-ui3-fw/view?usp=sharing
This hurts so much.