The children's charity NSPCC Cymru has said its Childline service has seen a worrying rise in calls from children with mental and emotional health problems.
Counselling sessions have risen by 13% since the pandemic began, the charity said.
In total 1,934 mental health counselling sessions have been delivered to children and young people from Wales between April and December 2020, an average of 215 every month.
Children and young people who contacted Childline had struggled with loneliness, low mood, low self-esteem, depression and anxiety.
A 12-year old girl from Wales who contacted Childline said: "My dad has left and cut off all contact with me and it has really affected me.
"I try to convince myself that I am ok, but I am really struggling and walk around with a fake smile.
"I tried to tell my mum how I feel, but she didn’t listen or understand, it was like she didn’t care.
"Dad abused and cheated on mum so I guess she finds it hard to hear that I miss him. I need help as I keep thinking about running away.”
A 15-year-old boy said: "I am feeling so overwhelmed and I am scared for my mental health. I am forcing myself to get out of bed and have lost interest in everything.
"I am scared that I am not going to succeed in life and feel like a freak. I used to self-harm but managed to stop, but I am getting strong urges to self-harm again.
"It is really nice to have someone to talk to who I won’t upset.”
Louise Israel, senior supervisor for Childline in Wales, said: “Since the latest national lockdown many children have been reaching out and talking about their emotional and mental health and Childline is continuing to support them with their worries."
The NSPCC said it is now urgently searching for more volunteers to work on the Childline service.
Childline Founder and President, Dame Esther Rantzen says: "With schools now shut again and children spending more time behind closed doors, it is absolutely imperative that Childline is there for them.
"Many young people, especially those in unsafe homes, are feeling desperately anxious and depressed. School can be the only safe haven they know, and without that support they feel entirely alone."