She famously went through a bitter £5.5billion divorce with ex husband James Stunt last year.
And Petra Ecclestone, 29, told MailOnline on Thursday that she it wasn't easy to adapt to life as a single mother of three children.
She said: 'It was lonely. It definitely was an isolating experience. [Being a mother] takes over your whole day and life.
Petra Ecclestone EXCLUSIVE: Heiress admits she felt 'lonely and isolated' following split from James Stunt, but is happier than ever with new love Sam Palmer (right)
'You don't get time for yourself if you're tired, to just put your feet up - and I don't like using a nanny. Having three children is intense. It's 24 hours a day.
'My sister Tamara has been an amazing support. She is my best friend and the person I always call if I need advice or someone to moan to.
'We are so different, but she has been there for me, through everything.'
Petra is mother to Lavinia, five, and twin sons, James and Andrew and has since found love with handsome Sam Palmer, who runs the LA Maddox gallery.
New venture: She has about to open Petra's Place, a centre a facility which provides support to children with autism, as well as their families (wearing a charity T-shirt by Mr Brainwash)
She said: 'I feel like I am in a good place. The kids are doing well and they're not in nappies now, they're growing up.
'We're all having a really nice time and living in LA, so there's lots of sunshine.'
Petra has previously spoken about her wish to have six children and Sam, who is sitting beside her during the interview (with a broken foot) doesn't flinch when she admits this is still her plan.
'I still want that,' she admits.'I really want to adopt. I don't mind from which country but I do not I don't want to adopt a baby as so many people want to do that.
'There are so many older kids who need a home and get overlooked, so that's what I want to do. Being with me, Sam went from having zero kids to three kids overnight.'
Doing what she can to help: Petra, pictured at the mFulham centre on Thursday, said she is frustrated by the lack of support given to parents with special needs children in the UK
Important: Petra's Place in Fulham has been two years in the making and opens in two weeks - it helps children with eating and sleeping, has sensory and themed rooms and gives parents a much-needed break