Those are symptoms of heat stress.. .
1) Get the rabbit to a cool area. Get a fan, and put it on him/her with a speed of medium or low.
2) Put a cold washcloth on the rabbit's ears. You could wrap ice cubes in a sturdy washcloth and apply to the inside and outside of the ears. The blood from the rest of the body will circulate into the rabbit's system once cooled. (Putting it in a cold bath or directly applying ice to it's ears is not recommended or good for the rabbit. That could lead into other problems of stress and shock to its system and you could lose the rabbit that way).
3) Put an old milk carton or soda bottle in the cage filled with cold water so that the rabbit can lean up against it.
4) You can dip your rabbit in a Lukewarm bath if it is almost lifeless. Dip up to the ears. Never immerse the rabbit completely in the water. You have to work on bringing its temperature down slowly.
5)Keep him/her hydrated, even if you have to put some Pedialyte (if you have any) or water in a syringe to give orally to keep the fluids in his system up. The rabbit may have to get an intravenous tube (a subq infusion).
5) Try to keep calm so that the rabbit doesn't get stressed.
