Sleepy Stacey Comerford, 15, suffers from a rare neurological disorder which means she enters a sleeping state for months at a time.
The last – her longest at TWO months – meant she missed NINE exams after being predicted straight As.
Stacey, from Telford, Shropshire, is just one of 1,000 people worldwide to suffer from Kleine Levin Syndrome also known as Sleeping Beauty Syndrome.
Stacey, who hopes to return to school part time, revealed she was taunted over the condition.
She said: “I’ve missed nine exams and my birthday in November.
“It’s easier now people know what it is. It’s easier to explain to them. Before, people didn’t believe me. That was the hardest thing.
“People would pull faces at school if I said I was tired and needed to go home.”
During an episode she can sleep for 20 hours a day and only gets up in a trance-like state to sip water or use the loo.
Mum Bernie Richards slips in some food to keep her alive before she makes it back to bed. Stacey has lost nearly two stone because of the condition.
Mum-of-six Bernie, 53, said: “There’s never any warning. I’ve even found her fast asleep on the kitchen floor.
“When she’s in an episode, she might get up to go to the toilet or get a drink but she’s not awake. I call it sleep mode.
“When she wakes, she thinks it’s the following day. She doesn’t have any memory of it.”
Bernie compares her daughter to Jekyll and Hyde.
She said: “It’s like having two different kids in the house.
“When she’s in sleep mode she can be quite moody but she can’t help it. She’s like a toddler who wants to do things her own way. She stamps her foot if she doesn’t get what she wants.”
Stacey began experiencing symptoms around a year ago but was only diagnosed in March.
Doctors initially thought she was just being a typical moody teenager.
But Bernie said: “All she wanted to do was sleep.
“The GP said ‘I know it sounds awful but she looks like a moody, depressed teenager’.”
Fears then surfaced she might have a brain tumour but tests came back negative.
The diagnosis finally came when she was seen by a neurologist at Birmingham Children’s Hospital.
But Stacey still gets taunted about her condition.
Bernie said: “She’s had that much stick off people. They don’t understand.
“I was even investigated by the local education authority because Stacey’s school thought I was deliberately keeping her out of school. They’ve stopped now we’ve got a diagnosis.
“I always knew there was something wrong. I know my daughter.
“She’s gone from a fresh faced teenager, full of energy to sleeping all the time.
“She could go to sleep tonight and wake up next week.”
There is no known cure for the syndrome but some suffers grow out of it.