The NHS has brought in new guidelines on endometriosis with the aim of reducing delays in treatment.
Endometriosis is a chronic condition which affects one in 10 women and can cause chronic pain, heavy periods, painful sex and depression.
Currently it takes, on average, seven years for women to get a diagnosis, which can mean years of unnecessary distress.
Doctors are now being told to listen much more to women who report symptoms.
Katie was diagnosed with endometriosis two years ago.
"I should never have got to the stage where I had chronic pain every day and I was bed-ridden," she tells Newsbeat.
She began documenting her journey on Instagram "to give a voice to women who can't talk openly about it".
She posts images and gives advice to others who may be newly diagnosed.
The 25-year-old has suffered from pain since she first started getting periods aged 14.
"I receive so many private messages from people of all ages," she says.
"Some girls message me who are 14, and they're pushing for a diagnosis. It's amazing to hear that they've even heard of it."
Throughout her teens and early 20s, doctors gave various reasons for Katie's extreme pain, including muscular problems, a urinary tract infection, irritable bowel syndrome, a sexually transmitted disease, and "part of growing up as a woman".
"I'd been with my boyfriend for seven years - it's not good when you have to go home and have to ask if he's been cheating on you, because the doctor thinks it might be an STD," she says.
"I felt like endometriosis took away my identity," she tells Newsbeat.
"I couldn't socialise, I couldn't exercise, it was hard to have a physical relationship with my boyfriend. It affected all aspects of my life."
She was finally diagnosed with endometriosis at age 23, and had surgery last year where cells were cut out of her body.
"It's is the closest thing we have to a cure at the moment but I know I may need to face more surgery in the future," she says.
And while Katie welcomes the new NHS guidelines, she feels there are other ways of informing people of endometriosis which are more effective.
Celebrities including Lena Dunham, Daisy Ridley and Halsey have opened up about living with it.
"I think it's great for these people with so much influence to talk about it because they're in a unique position where they can make a difference," says Katie.
"It's [also] about having the press talk about it. To me that's the main thing... that's when GPs will see it and read more about it - not necessarily just from the guidelines.
"If I'd heard about it, or if my mum had heard about it, she wouldn't have accepted me crying in bed with bad periods when I was a teenager."