There are many reasons for bad dreams and they can be cyclical, so it would be difficult to isolate if it is the med. The fact it is several years later suggests it might not be Prozac related.
Dreams occur every night but we forget most of them and think they just happen once in a while - they are generally meaningless so try to forget about them and see if the issue goes away.
As AnxiousNoMore said, this wouldn't be the kind of thing that can happen when one starts taking an antidepressant, but if you're also finding yourself suffering increased depression and/or anxiety lately, it could be a sign the drug is pooping out at the current dose. If everything is otherwise the same, then I wouldn't worry about it -- dreams are always weird.