And the Stags boss said it felt like they had let the army of fans down with a disappointing performance on the day that saw them fall at the final promotion hurdle.
“The hurt has eased fractionally, but I think it's going to be there for quite some time,” he said.
“We went into the game with a lot of optimism and it all dissipated within a 15 minute spell in the first half.
“It feels like an almighty kick in the 'privates'. There is a reason people say that phrase – because it hurts like hell when it happens. You curl up, you're bent double, then gradually the pain goes away a little bit.
“But the memory is always there of that kick – and the overwhelming feeling that we let everybody down. That stays.
“You saw the thousands that came down and supported us and we just couldn't manage to do it for them.
“We wanted that feeling for ourselves but also for everybody else – the memory we could have created down there that Port Vale enjoyed this year and we didn't.”
Clough has not yet watched the whole game back but knows the first goal was vital.
“I am not sure I will watch the game back though I have watched little isolated incidents,” he said.
“I know the first goal is absolutely massive and it seemed like every little thing on the day just went against us.
“We had a good chance to go 1-0 up, didn't take it. Then the deflected cross couldn't have fallen any more perfectly for their lad, straight in between Perch and Hawkins, and their lad buried it.
“Then we had one come back off the bar. It could have hit the bar and gone over or anywhere but just went straight to their lad.
“We had a good chance with Oatesy (Rhys Oates) which I think was about a centimetre from being over the line.
“If we hadn't had goal line technology it might even have been given.
“The sending-off then just meant it was almost certain we couldn't get back into the game.
“Oli Hawkins made a very, very poor decision in getting sent off.
“But you've got to remember he was probably man of the match in the two games against Northampton. He was outstanding in both games. He makes one rash decision and we are punished for it.”
Clough added: “I don't take a lot away from the day or the game. We will look at our preparation and talk to the players to see if we could have done anything differently.
“It was one of those games where it didn't happen for us.
“Second half when we changed I think we had more possession than them and, had Oatesy's goal gone in, we had a couple of skirmishes. You never know.
“But it was an almost impossible task at 2-0 down with 10 men at Wembley.”