Bunny that falls over like those sheep that get scared stiff.......?

Ok I have a Polish Chocolate Buck who is 6m old and I have had him for 5 days. He came from a freind that is a breeder. They kept him with ther other bunnys in there barn so they only seen him for abit during the days and when he was at shows. I keep him and my other bunny (1y broken black doe his mom side by side cages) in my house so I see them alot all day long. Well my Chocolate the day I brought him come just fell over like 8 times off and on for a hour and when he would hit the cage it was loud and he would be almost frozen I would talk to him and pet him and he would be ok. Well that was the end of it well yesterday he was munching his timothy hay and in mid munch fell over again its so loud when he dose it I am afraid he is gonna hurt him self and he just lays there for a bit like he is in a daze. My vet thinks ear infection but he dosent have the clic signs of a ear invfection. No tiling the head or hopping in circles. he dosent do this all the time just every few days