Donnie Wahlberg -- Hurricane Sandy FLOODED My Entire Apartment

Donnie Wahlberg's cereal bowl was floating across his kitchen last night ... after his apartment flooded due to Hurricane Sandy ... and he documented the entire situation on camera.

Wahlberg shot footage of himself sloshing his way through his flooded apartment ... a situation that became very common across the East Coast yesterday.

The New Kids on the Block member tweeted, "My entire building is under a foot of water. Awesome neighbors all banding together to help each other! Stay safe!"

A short time later, Wahlberg posted an update -- "Safe & Sound on Higher Ground! Don't worry about me. Material things are meaningless. Check in with those you know in the storm!"