Bindi Irwin felt "isolated" and "scared" before her endometriosis diagnosis.
The 24-year-old star - whose father was the late 'Crocodile Hunter' Steve Irwin - underwent explorative surgery last year after battling through more than a decade of pain and extreme fatigue with doctors finally concluding she was suffering from the agonising condition - which causes tissue similar to the lining of the uterus to grow in other places.
She has now explained she felt lost as she battled to find out what was causing her symptoms, telling PEOPLE: "You have to advocate for yourself. You can't take no for an answer because a lot of times I know I found it for 10 years. You feel so defeated when you can't find an answer. And it's really scary.
"I know with endometriosis, the sad thing is that it often doesn't show up on any scans. I got every scan under the sun, and nothing showed up. It wasn't until I had that exploratory surgery that they knew what was going on."
She added: "So you have to stay strong and surround yourself with people who love you and will be there for you no matter what. Because it's really scary when you don't have answers.
"You can feel very lonely. You can feel very isolated, but you have to hold on and you have to keep searching for answers no matter what. It is extremely important."
Bindi - who is mum to two-year-old daughter Grace Warrior with husband Chandler Powell - went public with her diagnosis in March revealing doctors found 37 lesions and a cyst during her surgery.
In a post on Instagram, she wrote: "For 10yrs I've struggled with insurmountable fatigue, pain and nausea. Trying to remain a positive person and hide the pain has been a very long road. "These last 10yrs have included many tests, doctors visits, scans, etc. A doctor told me it was simply something you deal with as a woman and I gave up entirely, trying to function through the pain ...
"I decided to undergo surgery for endometriosis ... Every part of my life was getting torn apart because of the pain. To cut a long story short, they found 37 lesions, some very deep and difficult to remove, a chocolate cyst.
"[The doctor's] first words to me when I was in recovery were, 'How did you live with this much pain?; Validation for years of pain is indescribable."
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