I have been creating quizzes & some of them aren't there any more. Why are they going away? And can I get them back?

They are being deleted because they are duplicate questions. I have left comments for you letting you know they are duplicates. There is a "search club" option near the topo, início of the page where you can check to see if a pergunta has already been asked before you post it. People who have been doing this trivia for awhile get really tired of perguntas that are asked over and over and denunciar them to be deleted. Hope this respostas your question.