Having spent most of my life in tornado alley in the US, the sensation of a building shaking and moving was not a new one--that happens in high winds, and usually is no cause for alarm. It was the rolling wave motion that woke me up fully to be aware this was not a high wind, almost as if someone was jumping up and down on the end of the bed.
Oddly, I never felt the least bit scared or panicked. Maybe I was just so tired I could not rally the energy. I was puzzled, curious and in the end went back to sleep.