A typically well-taken drop goal from the 2001 and 2005 Test Lion had given England the lead towards the end of a hard-fought battle but a 75th-minute try from fellow Lion Tommy Bowe saw the hosts suffer their first defeat of the campaign.
"It's disappointing. It's a hell of a feeling actually," said Wilkinson.
"I've not felt like this for a long time. They hurt more and more. It feels like we've taken a big bang.
"Right now it's hurting. I've felt that bad before in games. We lost playing for Toulon with the video ref in the last minute against Montpellier.
"They hit you hard, but right now it's because of spending a lot of time with these guys in camp. I know what winning that game could have done for us.
"It's a big fall when you lose it in the last minutes."
Wilkinson, whose defensive position arguably put him at fault for Bowe's late winner, has faced growing criticism for his own performances in an England shirt since the autumn internationals but the World Cup winning fly-half admits he remains his own biggest critic.
The 30-year-old has been off colour with his normally reliable boot so far in the 2010 Six Nations, while the backline as a whole have failed to shine against Wales, Italy or Ireland.
"I'm happy to do that. I don't necessarily choose to because it keeps you awake a bit but it's what drives you the next day to get up in the morning a bit earlier than most and get back on track," added Wilkinson, who played in five successive Tests for the Lions in Australia and New Zealand.
"I'm always critical. I'd be critical of my positional play for three-quarters of that match. I pride myself on being defensively reliable and it's definitely something I have to improve."
Those comments may suggest he remains overly critical of his own performances in an England shirt but Wilkinson is confident that he and his team-mates can bounce back for the remaining two games of the tournament.
Next up for England is a trip to Murrayfield to face Scotland in a fortnight's time, before a mouthwatering encounter with Grand Slam chasing France in Paris on March 20.
Wilkinson doesn't expect the games to get any easier but he believes that the current England squad have the potential to become a real force in world rugby once again.
"If we hit the levels we know we can we'll be in a good place. I wanted to see guys like Mathew Tait and Ugo Monye and Delon Armitage with the ball in their hands as often as possible.
"I've been in good squads before in all parts of the world and I get a good feeling about this one. You start to know that together you can do this.
"We know we are so close."