Sounds like symptoms of nosema ceranea to me. I lost some hives this year same as you. Did you see the queen? Treating with fumagillan - B or Fumadil is the mainstream approach. I've heard of at least one beekeeper that uses treatments of tea tree oil in sugar water syrup (7-10 drops in a quart of syrup). Nosema Apis needs treating in spring and fall, Nosema Ceranea causes problems in all times of the year. Best of luck to you.
"A good day is when no one shows up and you don't have to go anywhere." - Burt Shavitz (Burt's Buzz)