RADA-trained Raine (30), shot to fame last year playing Jenny Lee in the hit BBC1 drama, set in the 1950s in London's East End.
The actress, who returns in the second series on Sunday, said: "I've never experienced anything like that wave of attention before.
"I was appearing in The Changeling at the Young Vic in London at the end of last year and getting public transport every day.
"Overnight, I found myself being stared at on the Tube. You start to look behind you or think, 'Is there something on my face?' Thank God I really love the show -- can you imagine what it would be like if I didn't?"
Raine added: "The most common place I get stopped by fans is the ladies.
"If there's a queue outside, you're trapped because you need to go. But they're very good bonding places -- you always end up having great conversations in the loo."
The hit drama, based on the memoirs of Jennifer Worth, landed a second series just two episodes into its run after record audiences of almost 10 million viewers.
Raine said that she was "initially worried" that Call The Midwife would be a "chocolate-box, Sunday-night drama" but that it was saved by "gritty" elements.
She said viewers would find her alter-ego has become more "confident" and "even rather bossy" in the second series.
The actress said of filming scenes with babies: "This time, Miranda (Hart) got a wee-er, and I got a poo-er... In the Christmas special, during the birth scene at the beginning, the baby decided to poo on the lovely girl giving birth.
Raine admitted: "I do go through phases of feeling broody. When the babies are there, I go gaga over them and everyone says, 'You're broody'."