The home side, without 12-goal top scorer James Vaughan with an ankle injury, had no-one to finish off the host of chances they created.
But Reading took all three points thanks to on-loan Sharp's second goal in three starts.
Robins said: "I am frustrated because we have done everything except the bit that Billy Sharp does.
"That's what strikers get paid for and that's why they get the plaudits they do."
Robins claimed his side should have had two penalties and insisted Huddersfield should have won comfortably.
"Reading would not have been able to complain if we had run away with that game," he said.
"We should have had two clear penalties which on another day we would have got and we would have come out clear winners.
"I am proud and pleased, and the players have done everything I could have asked.
"It's just in the penalty box, amid the muck and bullets, where we need to keep a cool head."
Huddersfield dominated the first 20 minutes and came on strong in the second half but failed to take their chances.
Ward and Oliver Norwood both missed the target for Huddersfield before Martin Paterson struck a post in the 74th minute.
Sub Duane Holmes drove out of midfield and sent a pass to Dixon who cut the ball back for Paterson.
Town centre-back Joel Lynch was sent off in the fourth minute of stoppage time for his second bookable offence.
Robins said: "It was avoidable but we have to take it on the chin."