The 'Game of Thrones' actress has endured two health scares in 2011 and 2013 but only went public about her ordeal earlier this year and admitted she was terrified about making herself "vulnerable" by talking about her experiences.
She said: "The worries... That people will think your soul, your movement, your voice, who you were.
"It was nerve-racking to share it, to be honest. It always is, when you make yourself vulnerable. [I waited to talk about it because] I didn't want people to think of me as... sick."
The 33-year-old star admitted her medical history has made her more cautious about her health now and she finds it hard not to "think the worst" whenever she's feeling off colour.
She told the Observer magazine: "[There are still days on set when I take someone aside and say] 'I think I'm having a brain haemorrhage. I'm not, I promise, but maybe just put me in a cold tent and we'll sit down for a second, and I apologise in advance if I freak you out.'
"Over the summer I was burning the candle at both ends, and I was with my mate on the plane. And I was like, 'Dude, I feel really weird...' But I was fine.
"It's hard not to think the worst. It's hard to think you're overtired, or you've been on Instagram too long, and to realise these might have the same side-effects as something deadly."
The 'Last Christmas' star also views her ordeal as a "good thing" because it gave her perspective just as she was finding global fame as Daenerys Targaryen in 'Game of Thrones'.
She said: "And yes, I'm at the point where I definitely think of the brain haemorrhage as a good thing.
"Because I was never destined to be the 'young actor goes off the rails' type, up and down the gossip columns. And having a brain haemorrhage that coincided precisely with the beginning of my career and the beginning of a show that became something quite meaty, it gave me a perspective that I wouldn't have had otherwise.
"I'm quite a resilient human being, so a parent dying and brain haemorrhages coinciding with success and people following you in the street and getting stalkers - you're just, like, 'Well let's try and make something sensible of it.'