Dr says i have sinus infection. the floor feels like it's bouncing but does it so much more on hard floors. why?

?bouncing: I am not quite sure what you mean by "bouncing" of the floor, but if you were DX with a sinus infection, the infection can often refer symptoms to adjacent and connecting structures such as the inner ear (through eustacian tube travel of bacteria) and result in a type of inner ear/vestibular dysfunction causing dizziness or imbalance issues, maybe what you describe as a "bouncing?".