Dr diagnosed me with frontal sinus infection cause I am having dizziness and feel like floor bounces. Why does it do it worse in tiny rooms?

Vertigo. Dizziness and vertigo go hand in hand. With inflammation of the inner ear that can be the result of sinus problems, can get these symptoms. Because of the problem in the inner ear, the brain finds it hard to coordinate visual cues with those related to gravity and orientation. The small room may be worse because your balance system is more "stressed" visually.