How do I get rid of this roller coaster or sinking feeling when I lay down adn what is it?

I went to Elitch Gardens and rode a few roller coasters and I have had this feeling before. I tis always the night I ride a roller coaster I get this feeling when I lay down and close my eyes like I'm sinking into my bed or like I'm on a roller coaster. Can someone tell me what this is and why it happens?How do I get rid of this roller coaster or sinking feeling when I lay down adn what is it?
Vertigo??