My name is Eleanor and I have endometriosis. This was impossible for me to say for a long time. Not merely because I couldn't actually pronounce it, but also because it took six years of monthly vomiting, heavy bleeding, extraordinary levels of pain and eventually collapsing, for it to be diagnosed. Even after that, I have been reluctant to talk about it, for fear of it defining me, until now.

Statistics suggest endometriosis affects 200 million women worldwide, so you've definitely met someone with it. But, if it's as prevalent as arthritis and asthma, why don't we know about it?

[Managing symptoms of endometriosis, a disease affecting millions of women of childbearing age]

Although from the age of 11 I was missing a lot of school due to these terrible symptoms, the doctors told me that I 'just had bad periods, hopefully they'll settle down', so I would always go home, hoping they would. At 16, I was rushed to hospital but was told that 'periods are not an emergency, take some paracetamol - it's probably IBS'. Now I've been told that it was probably a ruptured ovarian cyst.

Being dismissed and belittled made me reluctant to seek further help so I tried to cope with the symptoms, which were worsening over the years, with no medication. It was only when I was 17 and collapsed in a drama class that I finally got help - and a name - for what was happening.

It turns out I had endometriosis; a disease that causes tissue similar to the lining of the uterus to grow in the peritoneum (the membrane lining the abdominal cavity), sometimes sticking organs together and forming cysts. No wonder I was passing out! The delay in my diagnosis was directly connected to the lack of awareness of the condition in society and within medicine. I was let down by the health system but also by my own ignorance; I didn't tell them the right information and they didn't ask the right questions.

Three months after my 18th birthday, I had a second laparoscopy to remove the diseased tissue. It's major surgery internally, but I was eager to get back to school. Two months later I sat my A-levels and began taking the pill. The surgery and hormones gave me some respite from the symptoms for a while, but I was still in the dark about the full nature of the disease.

But my life stopped and started. Roughly every 18 months, just as I'd managed to claw back my abdominal muscles and start my life back up again, I had to have another surgery.

I'm now 34 and my current tally is nine but the disease keeps growing (I'm hoping like other loyalty schemes, I'll get a free gift for the 10th.)

It takes an average of seven to 10 years for women to get a diagnosis and the treatments available are limited, often invasive, and there is no cure. There aren't enough specialists, research is underfunded and, because it's hard to get hold of accurate information, a lot of myths are perpetuated about this disease.

Even with a diagnosis, some doctors have told me this is 'all in my head.'

For 20 years, only those close to me knew I had endometriosis. It wasn't because I was embarrassed by it, but I feared that people would make assumptions about my capabilities or read the headlines and conclude I had a bad sex life and couldn't have children.

I coped by being busy and determined. Juggling the condition and a demanding career meant there was little energy left for much else. Relationships sometimes suffered or even broke down because of the intensity and 'adultness' of it all.

I spent my 20s as a comedian; creating the award-winning sketch group Lady Garden and doing character stand-up. In 2013, just after my first solo show at Edinburgh Festival, I collapsed. My body became too poorly and too unpredictable to continue as a comedian and actor. I began to write full time for well-known comics, and now I've written my first book, Private Parts, about living with endometriosis and all its funny and confusing aspects.

It's what I looked for but couldn't find when I needed a friend who knew what it was like, who could remind me of the world outside of the illness and make me laugh. My greatest joy is being able to include interviews with fellow sufferers.

And if sharing my story helps other women feel more empowered and hopeful - then perhaps endometriosis might have finally produced something rather good for once.

The Daily Telegraph