Felicia,

You can undelete almost anything in your class with these steps.

• Go to your course home page.  The URL should be something like https://yourschool.instructure.com/courses/somenumber 
• After the course number in the URL add "/undelete" so it is something like https://yourschool.instructure.com/courses/somenumber/undelete
• This page should show you content items which have been deleted from your course. The "last modified" date will be the date it was deleted.  If you find the quiz listed there simply click the Restore button and it will be recovered into your course.

Rick