The striker cost The Blades £6.8m from Preston 12 months ago but joined Bilic's promotion-seeking squad at the end of January.
He scored in the final game and admitted he doesn't know what the future might hold for him.
Robinson said: “I've enjoyed my time here, I came here to help the boys and I was able to do that.
“The lads have been doing it from August time. I've just tried my best and be committed. I'm just happy we got the job done.
“I've got to wait and see what happens. In the summer, in my head, I will go back to Sheffield United."