I called ERX today and asked them about this 6 day back order.
They said that last week the pharmacy was low on certain hydro's and it looked like it would be 6 days before it came in. However now they said that they restocked and there is no shortage of any meds. The auto-email is being generated and they haven't turned it off yet. My hydro was said to be at the pharmacy today (ordered yesterday ).
FYI
By the way ERX answers the phone right away now instead of the press 1 for this and press 2 for that.
Brutus