Shaun Maloney's injury-time free-kick meant struggling Rangers had to settle for a point from a game they had looked like winning despite having to play for 70 minutes with only 10 men after Bobby Zamora was sent off.
Loic Remy had fired the home side into the lead with a superb strike in the 85th minute.
Asked if he had encountered a tougher result to take as QPR manager, Redknapp replied: "All season? I don't think I've had a tougher result to take in my football career, never mind all season.
"We didn't deserve that, we deserved to win. It was a fantastic performance from everyone one of them. The result was criminal.
"Even with 10 men we deserved to win. The players are low, just like I am. Very low. You don't always get what you deserve in football, that's how it goes."
Zamora was shown the red card for kicking Jordi Gomez in the head with the boot of his outstretched left leg and will now miss crucial fixtures against Everton, Stoke and Reading as a result. Redknapp refused to defend the challenge.
"I thought it was a sending-off. It was a rash challenge. He is sorry, of course he is. Bobby is a good lad. I don't know why he did it, it is not like him," he added.
QPR are 19th in the Premier League table, seven points from safety.