Over-riding Quiz/Assignment submissions

[schaefera1]

I have inadvertently over-ridden Quiz responses from 18 students, after re-assigning the Quiz to a student that needed to complete it after the lock-out time.

Only that one student's responses are now there. I am hoping the other 18 responses can be retrieved somehow. I feel sick to the stomach as this was an Assessment Task, modified to complete online at home due to not being at school.

Would appreciate any assistance anyone can offer.

Thank you in hopeful anticipation!!