The Lethal Weapon 2 star split from DJ Jeremy Healy in April (10) and admits the break-up hit her hard.
She sometimes failed to shower or wash her hair and admits she looked like a "bag lady" - but pulled herself out of her gloom for the sake of her two sons.
Kensit tells Britain's Buzz magazine, "In the early days I didn't want to get out from under the duvet. Was I depressed? Oh God yes, absolutely. (My marriage) had failed and it wasn't even a year. But I couldn't hide under the covers for long because I had to show my kids that when something like this happens, you have to pick yourself up, dust yourself down, hold your head up and go.
"If I had gone under, what kind of mum would I be?... I was eating a box of doughnuts a day... Of course I blame myself for everything. I look back on all my marriages and think I should have done things differently."
Kensit was previously wed to Big Audio Dynamite frontman Dan Donovan, Simple Minds singer Jim Kerr and Oasis star Liam Gallagher.