The 30 Rock star, who is expecting her second child, confessed in her new memoir Bossypants that being unable to produce enough milk naturally left her feeling like a failure.
She says: "I chose to pump every two hours while watching the HBO series Entourage. I was able to do this for seven weeks before running out of episodes and sinking into a deep depression.
"However, the baby was thriving. I was no longer feeling trapped, spending 30 out of every 90 minutes attached to a Williams-Sonoma T*t Juicer. But I still had an overwhelming feeling of disappointment. I had failed at something that was supposed to be natural."
Fey added that she found the topic difficult to discuss with other people.
"I was defensive and grouchy whenever the topic came up. At a party where a friend was successfully nursing her little boy, I watched her husband produce a bottle of breast milk the size of a Big Gulp. It was more milk than I had produced in my whole seven weeks - I blame Entourage," she quipped.
Fey has also revealed that she agonised over the decision to have a second child.