Let me add about sleeping on pillows...
Sleeping on at least a 45 degree angle helps with usually any cause of your vertigo. (Not saying it will never happen, it can still happen and even happen sleeping straight up but it helps drastically)
With fluids in the inner ear, sleeping on the angel helps stabilize the fluid...laying flat or rolling over from one side to the other side can cause the room to spin, sleeping on extra pillows helps stabilize that fluid. Kinda the same theory of the middle of a big ship.
Also when the crystals dislodge and get into the inner ear (tubes where the fluid is) we feel it, the room will start to spin or we feel lightheaded or woozy...the rocks slow down the fluid in the inner ear, the fluid is what tells us what is up, down Etc and helps keep our balance.
Jerz