I was an energetic kid – always on the go and always dancing. Everything changed in 2014 when I was 15. I had pushed myself really hard in my GCSEs, and on the night of our leavers’ assembly, I did a dance performance and went to my prom – neither of which I remember. For about five days, I had no idea where I was or who I was with, and experienced my first panic attack. The GP put it down to stress.

Then mum and I left for a two-week holiday in Ireland, where I slept for 22 hours every day. Mum would wake me up to eat and drink, and to go to the toilet, then I’d be asleep again. I would get so angry at her if she tried to wake me. I don’t remember any of this – everything was relayed to me by Mum.

After another episode of sleeping 22 hours a day for five days, and another doctor not knowing what was wrong, Mum discovered Kleine-Levin Syndrome online. KLS is a neurological disorder characterised by excessive amounts of sleep, altered behaviour and a reduced understanding of the world. All my symptoms matched and finally, a year after it all started, I was diagnosed by a neurologist at Royal Devon & Exeter hospital. KLS is very rare – only 1,000 people around the world have it – and there’s no obvious explanation for it. Viruses, stress, injections and head injuries are all triggers, but not the cause.

I was relieved finally to have a diagnosis, because it was frustrating having everyone think I was just tired. From then on, every six to eight weeks, I would sleep for 22 hours a day in five- to nine-day cycles. No one knows how long KLS lasts; apparently it’s 13 years on average, but there are some people who have it for decades. I know my symptoms now: the day before an episode, it feels as if I’m drunk and can’t work out where I am or what I’m doing. I get really scared. I even think Mum is a different person. I’m terrified someone’s going to kill me, which is common among KLS sufferers.

When I am awake in an episode, I might as well be unconscious. My eyes are open, but my vision is blurry. It’s as if I am watching myself from above. Mum says the irises of my eyes become almost translucent. All I can think about is how much I want it to be over.

I got good GCSE results, then managed four AS-levels. But the second year of college was impossible – I was in for only three months. Every episode wipes my short-term memory, so revision was pointless. I got two A-levels, in dance and law, but I struggled because of the time I missed, and was even in an episode for one of my exams.

Before my A-levels, an episode would finish and I’d return to normal immediately, itching to see friends. Now, at the age of 19, my episodes last eight to nine days, and I’m not recovering in between. I never feel present.

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My family and friends are beginning to believe KLS is a real condition. I’m worried about friendships, though, because I go missing during episodes. I speak to friends on the phone one day and then I’m completely gone.

Last year, I was offered a place at Swansea University to study accounting and finance, but I had to turn it down. My episodes are so unpredictable. We discussed the possibility of flatmates helping out, but I don’t think they’d realise how much looking after I actually need. It’s like I’m a baby again.

A neuropsychologist at the Royal Cornwall hospital is doing cognitive testing on me to establish why I’m experiencing brain fog in between episodes. I’m hoping she can help with my short-term memory loss and slow brain processing, too.

I used to try to live as if I didn’t have KLS, and then, when an episode came, I’d just accept it and ride it out. But because I never properly recover from my episodes now, it stops me from leading a normal life.

I am, however, learning how to deal with it – I try to get out a couple of times a week, and can just about figure out where I am and hold a conversation. I have to take it one day at a time.

• As told to Megan Carnegie Brown

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