A woman was misdiagnosed with an 'eating disorder' after she dropped 8 stone in just one year while unknowingly battling thyroid cancer.

Cerys Head, 22, from Exeter, who weighed 18 stone at the age of 16, told MailOnline FEMAIL how she sought medical help after her weight suddenly began to spiral out of control - with experts concluding that she was starving herself.

The student lost almost half her body weight before being diagnosed with cancer and undergoing undergoing life-saving surgery in which she had a golf ball-sized tumour removed from her neck.

Cerys Head, 22, from Exeter, lost almost half her body weight before undergoing life-saving surgery in which she had a golf ball-sized tumour removed from her neck. Aged 16, Cerys was 18 stone and wore a size 22/ 24; but after dropping a huge amount of weight she hit the gym and got back into shape

Cerys - who was 18 stone and wore a size 22/ 24 - was subsequently diagnosed with metastatic thyroid cancer and had her entire thyroid gland and all the lymph nodes on the left-hand side of her neck removed

Cerys shows off the huge scar on her neck where her thyroid gland and all the lymph nodes on the left-hand side of her neck removed in 2015 - after doctors put her weight loss down to an eating disorder

Doctors initially misinterpreted Cerys being constantly fatigued, freezing cold, having trouble sleeping and experiencing sudden weight loss - putting it down to a poor diet.

After struggling through her first year of university, Cerys was finally referred to a consultant two years ago aged 20, when a huge lump the size of a golf ball' appeared on her neck.

She was subsequently diagnosed with metastatic thyroid cancer and had her entire thyroid gland and all the lymph nodes on the left-hand side of her neck removed.

Since her life-saving operation, Cerys has made it her mission to get fit and raise money for the charity Clic Sargent, who helped her through her illness, as well as the Butterfly Thyroid Cancer Trust.

Cerys as a teen, before she lost almost half her body weight. Doctors initially missed the signs of her being constantly fatigued and freezing cold - putting it down to a poor diet

Cerys, left, before she fell sick. The student had soared to 18 stone by the age of 16, but she sought medical help after her weight suddenly and rapidly began to spiral out of control

The student at her heaviest. She lost almost half her body weight before undergoing life-saving surgery in which she had a golf ball-sized tumour removed from her neck

Cerys (pictured before her weight loss) admitted she was keen to lose a few pounds but she rapidly shrank from a size 22 to a size 10 - leading to concerns from doctors

WHAT ARE THE SYMPTOMS OF THYROID CANCER? The main symptom of thyroid cancer is a lump in the front of the neck. But the disease tends to develop slowly and may not cause any symptoms at first. Thyroid cancer often causes a painless lump or swelling low down in the front of the neck. However, neck lumps are common and are usually caused by a less serious condition, such as an enlarged thyroid. Only around 1 in every 20 is cancer. A lump is more likely to be cancer if it: See your GP if you have a swelling or lump at the front of your neck. While it's unlikely to be cancer, it's important to get it checked out. Other symptoms include: Rarely, thyroid cancer can affect the production of thyroid hormones and cause diarrhoea and flushing. Source: NHS Choices Advertisement

Cerys, who lives with her boyfriend James and is studying for psychology degree, told MailOnline: 'I'd always maintained a healthy diet throughout my life even before I decided I want to lose the weight.

'So when I started to lose the weight so dramatically, it was a shock and I didn't know what was happening.

'I had dropped a lot of weight in a little amount of time. It was noticeable by everyone around me, including my teachers at school who expressed their concerns.

'My mum wasn't sure what was going on either and often questioned how I was feeling and my energy.

'I would say I felt fine, but was experiencing a lot of fatigue – which I put down to a busy day at school and exam stress. etc – and I was cold all the time.

Cerys, who lives with her boyfriend James and is studying for psychology degree, told MailOnline: 'I'd always maintained a healthy diet throughout my life even before I decided I want to lose the weight'

Cerys, far left, with friends. After struggling through her first year of university, Cerys was finally referred to a consultant two years ago after a huge lump the size of a golf ball' appeared on her neck

Speaking about her illness, Cerys (right) recalled: 'I would say I felt fine, but was experiencing a lot of fatigue – which I put down to a busy day at school and exam stress. etc – and I was cold all the time'

'I had difficulty sleeping and would wake up several times during the night. This continued up to the point I went to my doctor who asked me lots of questions about my lifestyle and diet and seemed to miss my other symptoms, which is where the mistake was made.

'The doctor suggested I try and eat more and wear more layers and make sure I get enough sleep and water, they suggested that I was always cold because I'd lost a lot of weight very quickly.'

Following the doctors' advice, Cerys tried to rest and eat more, 'battling' through her exams and winning a place at university.

She recalled: 'My symptoms at uni got a lot worse, I was so cold I couldn't leave my room, I would sit next to the heater all wrapped up just trying to keep warm.

Cerys with boyfriend James, who she lives with, at a National Youth Brass Band of Wales concert. Following the doctors' advice, Cerys tried to rest and eat more, 'battling' through her exams and winning a place at university - before eventually being diagnosed with cancer

Unrecognisable: After the procedure, Cerys' weight dropped to 9 stone 7 lbs and she battled depression, anxiety and fatigue, as well as struggling with everyday activities

'I still continued to try and eat plenty, I often had huge portions of pasta for lunch and dinner along with lean meats and vegetables.

'My social life took a hit because I could no longer go out to parties, I was just too cold, and I couldn't go to any socials.'

Despite several visits to health professionals and her weight 'fluctuating', Cerys was repeatedly advised to practice a 'sleep routine', manage her stress levels and eat well - all of which made no difference to her health.

Finally, in April 2015, she noticed a large lump in her neck and after extensive tests she was sent for life-saving surgery on 19th July that year, followed by two doses of radioactive iodine.

After the procedure, Cerys' weight dropped to 9 stone 7 lbs and she initially battled depression, anxiety and fatigue, as well as struggling with everyday activities such as showering.

Cerys (pictured with boyfriend James) has taken part in several half-marathons and fitness challenges, having raised over £2,000 for Clic Sargent who helped her throughout her recovery

Healthier than ever: As well as embarking on a healthy diet, Cerys (pictured with James) began using USN supplements to boost her calorie intake and energy levels

Transformation: Cerys says she is 'stronger, more confident and more able to take on life's challenges' and credits her family with encouraging her road to recovery

She recalled: 'After the surgery I was very weak, and I lost huge amounts of strength and muscle mass.

'My journey back into my gym and fitness routine was slow, at the start I could only manage five minutes walking on a treadmill.'

As well as embarking on a healthy diet, she began using USN supplements to boost her calorie intake and energy levels.

Two years on, Cerys says she is 'stronger, more confident and more able to take on life's challenges' and credits her family with encouraging her road to recovery.

She now weighs a much healthier 12 stone 8 lbs, and has taken part in several half-marathons and fitness challenges, having raised over £2,000 for Clic Sargent who helped her throughout her recovery.

Sports nutrition company USN is currently running a body makeover challenge. To enter visitusnbodymakeover.co.uk