A woman who spent decades being told that crippling pain was just part of the deal has lost more than half her body weight after surgery finally did what years of suffering apparently couldn't: make her feel like a functioning human being.

Carys Thurlby, 43, from Worcester, dropped 10 stone (140lbs) in 18 months following a hysterectomy that she says brought lasting relief from endometriosis pain and exhaustion. The transformation, she said, was "night and day" - a phrase that suggests the previous setting was "permanent darkness."

Thurlby believes she had been living with endometriosis since she started her periods as a teenager, which means she spent her GCSE exams "chewing on paracetamol" while pain radiated through her pelvis and legs. Because nothing says "normal adolescence" like treating a chronic condition with the same medication you'd use for a mild headache.

"I didn't really know that being in so much pain each month was not normal," she said. "I didn't really know that what I was experiencing wasn't what women were meant to experience."

She was diagnosed at 19 after a laparoscopy performed when the pain became "excruciating." Her reaction to the diagnosis was refreshingly honest: "That was the first time I had ever heard of it." Endometriosis, which affects multiple parts of the body and has no cure, is apparently one of those conditions that remains a well-kept secret until it's actively ruining your life.

Over the years, Thurlby had several operations, but the relief was only temporary. Her ovaries were eventually removed after being damaged by the condition, and she later underwent a hysterectomy. Because sometimes the only way to stop a body from attacking itself is to remove the parts it's attacking.

She said chronic pain and fatigue affected every aspect of her life as she balanced raising children with her career. "I can't describe how different it felt," she said of the post-surgery reality. "It was a real shock to me to understand this is how normal people function, and not to accommodate pain and fatigue into everyday life."

Before the surgery, Thurlby relied on sugar for quick bursts of energy just to get through the day. "The idea that I would then go out and exercise or move, even a gentle walk to the shops, was just not on the cards," she said. "There was no room in my life for me to look after my wellness."

Once her health improved, the weight came off. She gained confidence, started exercising, and discovered a passion for running. Eighteen months ago, she couldn't run for more than a minute. Since then, she has completed the Worcester Half Marathon and is training for next year's London Marathon - a sentence that would have been medically implausible not long ago.

Her experience is shared by Vicki Shattock, from Belbroughton, who has written a book about her own struggle to have health concerns taken seriously. Shattock urged women experiencing persistent pain to trust their instincts. "You know your body better than anyone," she said. "If someone is telling you pain is normal and you know it isn't, don't let it go."

The takeaway, beyond the obvious triumph of finally getting appropriate care: when a woman says something is wrong, maybe believe her the first time.