Published Sunday, 13 April 2014
The Smile singer suffered her first miscarriage in 2008.
Then in 2010, when was six months pregnant, she lost her first child with now-husband Sam Cooper. Days later, she was rushed to hospital with septicaemia and Allen reveals she almost died, but felt too numb from the loss of her child to care.
She tells The Sun on Sunday: "It was horrendous and something I would not wish on my worst enemy. It's something that I still haven't dealt with. I never will get over it. I have dealt with it, you know, as being at one with it. But it's not something you get over. I held my child and it was really horrific and painful - one of the hardest things that can happen to a person.
"I was overwhelmed by what an incredibly unlucky thing it was to happen. But I had this man standing by my side, who I knew was going to be with me for the rest of my life.
"I nearly died. But I was numb and I didn't care. I'd just lost my baby and that is a reflection of how numb I was."
Allen thinks about her unborn son every day, adding: "We've got a little stone in our garden with his name on. And lots of different things that I do, rituals, I have him in my mind."
The singer now has daughters, two-year-old Ethel and 15-month-old Marnie.