Forms have a property called Has Module. If you change this to "No", your module will be discarded. Could you possibly have done, by accident perhaps, before you saved the form?
Otherwise, I'd have to call it a bug, though I never heard of it before.
I once read something about recovering database objects that were accidentally deleted, but it's probably too late in this case. I think it involved opening a new Access instance, creating a database, and importing the deleted object into it. It worked because the deletion isn't actually final right away; if you did this right away, you could still get the deleted object back. But it wouldn't work if you closed the database or did much editing within it before you tried to recover, and in any case I'm not sure it would have worked for a form module, which is only part of a database object. Rick Sprague