Where are you flying into and out of? Naples is closest and if so then I would move Naples from the 28th to the 29th and actually stay in Naples for at least the night before your flight and I would recommend two nights so you can explore Naples for the full day before your flight.
I would read up on the mechanics of getting from Sorrento to the Amalfi coast before you go since it can be logistically difficult, but hopefully not that crowded in May.
You might also think about moving your "Sorrento" day to the beginning of your trip so you're not charging off to Pompeii for a physically and mentally challenging day for your first day in Italy.
Have a great trip,
=Tod