TOUGH CROWD on spring break this year — singer Jeremih took the stage for a special performance in Texas Wednesday night … and when the crowd realized he was lip-syncing, they BOMBARDED him with drinks … driving him offstage.

It all went down at Clayton’s Bar and Grill on South Padre Island — sources tell TMZ, the crowd was already pissed because Jeremih was two hours late to the show … and when they discovered he wasn’t even singing, they went off the rails.

Jeremih opened his set by “singing” his song “Down on Me” — he barely got started before the crowd drowned him out with boo’s … and someone tossed a bottle.

Jeremih powered on — but then some jackass throws a full drink at the guy, dousing him in a disgusting spring break cocktail, and J calls it quits … walking offstage.

All in all, we’re told the concert barely lasted a few minutes — and the bar ain’t refunding the $30 tickets. Calls to Jeremih’s camp were not returned.