"It feels like a defeat just like Saturday felt like a win," said Fox, whose strike against the Lions was his first for Norwich since joining from Colchester in the summer.
"If we had taken away the two last minute goals, we'd have been beaten on Saturday but won here and we'd have been a point better off.
"It's very disappointing but we've seen both sides of it now and we've got to learn from it."
Since arriving from the U's, Fox has seen limited first-team action, but a series of injuries and suspensions in recent weeks enabled him to pick up his third league start of the campaign against Millwall.
And fellow midfielder Matt Gill, whose long-range throw set up Fox's goal, made his first City appearance since returning from a loan spell at Peterborough United.
I think you've just got to go into it thinking that it's the most important game of your life
Norwich City midfielder David Fox
"When you do come on, you've got to make an impression and that's what he did and with my goal that's what I've done," Fox continued.
"When you get these opportunities you've got to take them and I think you've just got to go into it thinking that it's the most important game of your life.
"That's what I've done and whether or not I stay in the team I don't know.
"But if I don't at least I know that I've given it everything and put in a shift for the boys and I'll have to wait for my next chance."
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