Only a few world online ? Dropping a number of worlds every day??!!!!
Think you are way out to correct the game?
It is not the worlds who is the problem, they did work fine untill yesterday.
1. Clear history
2. logg in
3. enter last world you was logged in to
4. switch world under option in the game. right tab/window
5. Tips. if you have two sides open you can trick to enter two worlds, and moore.