The long-serving Lions defender was sent off for the second time this season, and the 10th in his career, during Saturday's 5-2 defeat at Bournemouth.
Dunne was booked early on for a foul and then shown a second yellow for handball and now faces a two-match ban.
But he told the club's website: "If you look at the two games, against Brighton and Bournemouth, I've probably made only three tackles.
"It's a frustrating one for me because when you get a booking, particularly one early in a game, it's always in the back of your mind and that can affect how you play from that point onwards.
"You're wary that if you make one more tackle you could be off, but that's something that professional footballers have always had to deal with and I'm no exception to that.
"The handball is a frustrating one because yes, it has hit my hand, but my arms were down by my side and the only way I could have got them out the way would have been for them to be behind my back.
"Naturally I'm disappointed that I'll now miss two games, and big ones at that against QPR and Reading."