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Drew Barrymore opens up to PEOPLE about her battle with postpartum depression after giving birth to her second baby. Drew shares, "I didn't have postpartum the first time so I didn't understand it because I was like, 'I feel great!' "

"The second time, I was like, 'Oh, whoa, I see what people talk about now. I understand,' " the "50 First Dates" actress continues, "It's a different type of overwhelming with the second. I really got under the cloud." The mother of 3-year-old Olive and 18-month-old Frankie adds the experience was "short-lived, probably six months."

Drew, however, is grateful with the experience which always reminds her to stay present in the moment. "It's really important. I was in the kids' class with Frankie and Olive this morning and I started fretting about some piece of work news that was just stressful," she recalls. "You know, in like the Broadway Babies class and it's the one-hit wonders day, and they're singing I don't even know what song, and we're all doing our lollipop drums and I just thought, 'Save it until after class.' One thing at a time."

Drew says her life with husband Will Kopelman "is an abundance," adding that "it's perfect and totally imperfect."

The "Blended" actress, whose new book "Wildflower" hits the bookstore on October 27 and upcoming film "Miss You Already" hits theaters next month, wants her daughter to see her working as good thing.

"Putting a negative stigma on work is a go-to. It makes us feel like it proves to our children that we don't want to work, we'd rather be with you," she explains, "I want them to see that work can be a good, positive, fun, happy thing. I've worked since I was 11 1/2 months old so I have to be able to work, too. But I have to put them first. I don't know if it's good enough for anyone but I'm doing my best."