Orlando Bloom Parties Like a Wild Man -- I'M HAPPY!!!!

Orlando Bloom is not acting like the loser of the Justin Bieber scuffle ... he looks like he's having the best time of his life at a restaurant near Ibiza.

Orlando looks a little -- well, buzzed -- as he dances furiously to "Happy" ... flailing his arms in the air.

At one point he pulls what appears to be his GF -- Erica Packer -- up on the bench he's dancing on and kisses her hand.

But Erica does not have a monopoly on Orlando. A bunch of chicks swarm him as he dances uncontrollably.