The findings suggest that the youngest generation is suffering depression, anxiety and loneliness.
The Trust is warning that children will need dedicated support lasting months.
But many of the charities and organisations that offer help are also running short of funds due to the pandemic.
ITV News spoke to three children for an insight into what they are going through.
Amelie aged seven told us: "I didn't have nightmares often, now I have them every day, because I'm still really scared and I don't want to get it.
"The most big worry is about school, because it's very near Year 2, so the next time I'll be in Year 3.
"Because of the coronavirus, I haven't learnt that much."
Neneh is also seven and her mum works in a care home.
She told us: "Everyday when my mum goes off to work, I think why does my mum want to work in the care home?
"When she goes to work she washes her hands and puts on gloves and a mask, I'm thinking what if my mum dies of the coronavirus?"
Jaylah is six and she is worried that her mum is crying more often.
She explained: "For my mum it's scary, she's crying a lot....these coronavirus times is not easy, it's very hard"
Chief Executive of the Childhood Trust, Laurence Guinness, told ITV News if we don't help children, particularly the poorest of children, we could be "facing a real tsunami of need".
He said: "Child after child after child told me how disturbed they were, how they are having nightmares, how they were scared to go outside because they thought they were going to die.
"We've completely underestimated the impact this pandemic has had on children and we've forgotten the messaging might have have disturbed children.
"So children actually, well the poorest children have suffered the worst who have been living under one room have gone hungry, who've not had any education whatsoever because they've had no laptop or broadband access, these children are desperate for some reparation, they're desperate for support, we need to help them recover and if we don't we could be facing a real tsunami of need."
Candice James, Manager of Loughborough Community Centre in Brixton said: "Making sure our families can access the right nutrition to be able to live healthy and happy lives has been hit terribly.
"What we've seen from our parents is that food with lower nutrition is much cheaper, so much easier to get but at a time when they've been at home and having to feed a whole family on less income and the cost of living being raised has been extremely difficult and it adds to their anxiety levels and it exaggerates the home situation because everything just gets heightened."
The Childhood Trust supports dozens of community projects to help children, but fund raising has been much harder during lockdown, many events that were planned have been scrapped.
A campaign called Champions for Children aims to support nearly 100 schemes that help youngsters cope with the changes coronavirus has brought to some of the most precious years of their lives.
Donations can be made here.