I survived stage 4 cancer as a new mom, but couldn't return to my job or have more kids. But I found a new, fulfilling career.

• When Ceinwen Giles was diagnosed with cancer at 34, it changed her life.
• She didn't know anyone her age with cancer, so she started organizing coffee meetups to find them.
• It grew into a charity that connects the rising number of younger adults experiencing cancer.

This as-told-to essay is based on a conversation with Ceinwen Giles, 48, co-CEO of Shine Cancer Support, who lives in London. The following has been edited for length and clarity.

Weeks after giving birth to my first child at 34, I was diagnosed with stage four cancer.

I felt quite unwell during my pregnancy but never suspected it was anything other than normal. Even when I was hospitalized with swollen legs and high blood pressure, I still didn't think anything was really wrong.

Over that hospital stay, I had terrible chest pain and got sicker and sicker. I ended up giving birth to my daughter six weeks prematurely via emergency c-section. My tiny daughter and I stayed in hospital for another three weeks, but my health just kept getting worse.

We managed to get home, but soon after, I was hospitalized again with terrible back pain. I couldn't eat and had no energy. The doctors still thought it was pregnancy complications. It took them another three weeks to diagnose me with non-Hodgkin lymphoma, a type of blood cancer, on February 4, 2010.

I had wanted to know what was wrong with me because I was so unwell, nobody knew why, and that was an awful feeling. But then to be told I had cancer was just completely shocking. I had no idea that that was even a possibility. I was really scared that I might die.

I had a six-week-old baby, and I had been looking forward to spending my maternity leave with her. I remember just thinking, "I don't know what to do," because my husband only had two weeks of paternity leave. Luckily, his employer was very understanding, and we had lots of support from friends and family.

By the time I was diagnosed, the cancer had spread all over my body and I was told I had a 40% chance of survival. They said my best option was to stay in the hospital on a clinical trial for six months and do a high-dose chemotherapy. So that was what I did, and thankfully, I'm still here 14 years later.

Treatment left a permanent mark

I don't think that there was any part of my life that wasn't affected by cancer. It's not just the diagnosis. It's a lot of the things around it that are really difficult.

I spent my maternity leave getting chemotherapy, worried I was going to die. I was the first of any of my friends to have a significant illness. They were shocked. A lot of them were great and really stepped up, but some people don't know how to deal with it. They don't want to talk about it.

About six weeks after I finished treatment, I had a scan, and the doctors said they couldn't see any evidence of disease. Obviously, that was good news, but I still had a high risk of relapse, which left me hypervigilant and anxious. Plus, the treatment left permanent marks on my health and body.

I had always wanted to have three children, but chemo affects your fertility, and I was told before I started treatment that I wouldn't be able to have more children.

Before I got ill, I was an international development consultant, and I often worked in West Africa with communities affected by conflict or disease. I had planned to start my own business as a freelance consultant, but chemo left me with immune deficiencies that made it unsafe for me to travel to some developing countries.

I remember asking my hematologist, "Can I go to Sierra Leone?" And he was like, "Absolutely not." So I could no longer do my job in the same way. I went back to work in the office three days a week because I was still recovering, and that had a financial impact.

I could no longer exercise as much as I used to, and I couldn't relate to my peers anymore. I had to rebuild everything from scratch.

I didn't know anyone my age with cancer

I felt very lonely because I couldn't find anyone my age with cancer. I felt like I was the only person that this had happened to, and that there weren't any resources for coping at a younger age.

Luckily, someone told me about a woman they knew called Emma Willis who lived on the other side of the country. She was diagnosed with breast cancer when she was 29 and was organizing coffees for younger adults with cancer.

I emailed her and we arranged to meet when she was next coming up to London. We had a great chat, and soon I started arranging meetups of my own.

We ran a survey about the issues young people with cancer face, something I used to do at my old job, and a few hundred people filled it in. We found that fertility, work, friendship, and mental health were consistent issues.

We put on a workshop to find out what people thought of the survey results and we couldn't get the attendees to leave because they were having such a good time.

That's when we thought, "We're onto something here," and we grew from there. We registered as a charity called Shine in 2012, and it's now a full-time job for both of us.

We've got about 17 support groups around the country, all run by volunteers who have had cancer themselves, a conference in October, and a camping trip in August.

We always say it's a community you wouldn't want to join, but if you've got to, it's better that there's a community to support you.