After months of struggling both mentally and physically to do simple tasks, dealing with a constantly foggy brain and serious exhaustion that wouldn't go away no matter how much I slept, a doctor told me I had chronic fatigue syndrome (CFS).

Having never heard of it, my response was sceptical, and somewhat annoyed - similar to when you're told "it's only a virus" after having a miserable cold for weeks on end.

It felt like a cop-out. But when she told me that there was a chance it would never go away, and the only way to help it was to "avoid exerting too much energy", I decided to do my research.

That was 2.5 years ago. Since then, I've learned many things about CFS, including what it is and, just as importantly, what it isn't.

So, what is it?

Officially called myalgic encephalomyelitis (ME), the condition involves extreme levels of fatigue which last a long period of time, disrupting your daily life. Rest does not help alleviate the symptoms. It is thought to effect 17 million people worldwide, and four times as many women as men.

In 2015, a report by the American Institute of Medicine defined ME as "an acquired, chronic multi-systemic diseases biological in nature". It added that the symptoms included "immune, neurological and cognitive impairment".

While there is no proven cause (and no official diagnostic test), it appears that most cases seem to be triggered by viral infections like glandular fever.

The condition has been around since the 20th century. An outbreak hit the Royal Free Hospital in London in the 1950s, followed by Lake Tahoe, Nevada in the 1980s where the epidemic was nicknamed "Raggedy Ann". After that, cases started to crop up all over the world.

Living with CFS feels like being tired all the time. But CFS is so much more than just being tired.

Like many others, my CFS was triggered by a miserable bout of the Mumps (yes, people still get the Mumps).

Once the virus was gone, I was left feeling completely wiped for weeks, to the point where even walking up the stairs to my flat made me need to lie down. It also came along with headaches and a foggy feeling in my brain which made it hard to concentrate.

All in all, staying in bed seemed like the best (or sometimes only) option - yet sleeping didn't make me feel better.

Potentially the worst part was the likelihood that it might not go away.

A 2011 study published in medical journal The Lancet had originally suggested that the illness could be made better with exercise, but an analysis of the data years later showed that as long as you're already getting standard medical care, the chances of being helped by treatment are 10 percent at best. The chances of recovery are almost none.

As a Master's student at the time of diagnosis, I faced a challenging few months trying to stay on top of course work. Luckily, good relationships with my professors, hard work and the timing of the illness - it hit me right as course work was finishing - saw me through, but not everyone is as lucky.

student at Oxford University who got ME during the final year of her degree following a bout of glandular fever had requests for extensions on her course work denied, and many others have faced similar problems.

According to the BBC, one in 100 children also miss at least one day of class a week because of CFS.

This becomes a bit more complicated for working adults. In the first full-time reporting role I took on after graduating, I found it difficult to explain to a manager that some days I was too exhausted to come in to work, but the likelihood was I wouldn't feel better after some rest.

There was little I could do. Working out, which I loved to do, made it worse, and eating only provided me with fleeting bursts of caloric energy.

Luckily, by giving myself the time I needed and trying not to push myself too hard, I started to feel better with time, staying home or cancelling plans when I didn't feel up to it.

Eventually I hardly struggled with the fatigue and started exercising regularly again - I had close to a year with no symptoms at all, and felt better and became fitter than I ever had been. I even managed to train for and complete a half-marathon.

Although it's much better than before, it still comes back in bursts.

The worst part, though, is that sometimes when I see new doctors, they suggest my illness is purely psychological. This happened to me earlier this year, when I visited a different doctor for advice.

She suggested, as many do, that the illness was all in my mind, and that I should see a therapist.

Many health professionals continue to have a similar response, and dismiss the disease as "all in the mind".

According to The Guardian, a survey in the UK carried out by the ME Association early this year found that 46 percent of patients thought that the care provided by their GP for CFS was "poor" or "dreadful".

Some 18 percent had no contact with their GP at all as they found they made their illness worse by not taking them seriously.

The National Institute of Health in the US launched plans to research people with CFS in 2015, with director Francis Collins stating:

"Of the many mysterious human illnesses that science has yet to unravel, ME/CFS has proven to be one of the most challenging.

I am hopeful that renewed research focus will lead us toward identifying the cause of this perplexing and debilitating disease so that new prevention and treatment strategies can be developed."

And it does seem that the disease is starting to get the attention it deserves. Earlier this month, the NHS announced that is is trial ling a therapy to treat two-thirds of the children who suffer from CFS.

By using online behavioural therapy sessions on 734 children, the trial aims to adjust children's sleeping habits and activity levels to try and adapt the way they live and alleviate the symptoms.

However, for me, being pushed to do more exercise, sleep more, or try therapy certainly wasn't the answer.

While any research or trial on the topic can only be a good thing, the next step should be encouraging people to take the time and rest they need when they need it, both physically and mentally - and fostering an environment in schools and workplaces that allows them to do so.

This article was originally published by Business Insider.