The result has left them in the bottom three of the Barclays Premier League and increased the pressure on boss Chris Hughton.
Martin said: "It hurts - simple as that. It's humiliating.
"We've let ourselves down and we've let the manager down.
"There is going to be a lot of soul-searching and conversation about this game, analysing it and going through it.
"We will see what we are made of now for next week.
"We have got the characters in the dressing room. It is a good dressing room, a confident dressing room. We believe we are good enough to be in this league.
"Next week we will see what we are really made of."
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