I have 2009, there is a sump under the shower pan but not a 'real' sump. Run the pump while you are showering. Also, as others have mentioned, if you still have the original Italian-style 'quiet pump' that is incredibly impossible to rebuild - be sure to clean the intake strainer. Especially if you have ladies or cats aboard. For whichever showers you use, strongly recommend replacing with a whale gulper or similar and save the old pump for a spare in the galley.
Not sure if mine is different somehow (I guess there were changes with these boats during the ~2008 economic fiasco), but once again no real sump. Everything below the shower is a dead drop to the pump, and forward shower which I have goes straight from drain to pump and then a few feet back up and overboard. We keep the forward head & area as sort of a 'walk in closet/shower/grooming' area and primarily use the aft head for regular use and the shower there for storage nowadays so your mileage might vary. Hunter docs show a sump, but there are none on the ~2009 for sure.
Possibly one detail to check if you have a sump or not is whether there is a relay that triggers the pump when the sump fills up. My boat has none.