McCarthy told Entertainment Tonight that her recent career success has been difficult to process and said that she feels honoured to be recognised by her colleagues in the industry.
"I just about fell over. My knees buckled and I thought, 'This is a weird time to flub the teleprompter'," she recalled of learning of her nomination.
McCarthy continued: "I was waiting for the producer to come out and say, 'Sorry, she's not nominated - our bad!' I legitimately thought it was my turn to talk and I forgot part of the script and I was gonna make it so awkward.
"You know, it's so great when the audience likes what you're doing, but it's a totally different thing when your peers say, 'Good job!' I mean, to be put in that category with those women is a weird thing because I don't put myself at that table... but I love that table.
McCarthy explained that she is still struggling to believe that she has been nominated, quipping: "I would clear the plates to be near that table, so it's still hard to imagine that I have a seat there.
"I'm still thinking they'll ask me to bus the table, so to hear 'Come on in...' It's overwhelming."