The former couple split in 2013 after three years of marriage, and it took its toll on "naturally positive" Miranda.
Miranda Kerr has said she was depressed after her split from Orlando Bloom
"My mom used to call me a 'giggling Gert' because I was always laughing, even in my sleep," Miranda told ELLE Canada. "When Orlando and I separated, I actually fell into a really bad depression. I never understood the depth of that feeling or the reality of that because I was naturally a very happy person."
However Miranda says she got through it by learning that "every thought you have affects your reality and only you have control of you mind."
The 33-year-old now amicably co-parents her son Flynn, five, with Orlando, and says that his happiness comes first.
The model is now engaged to Evan Spiegel
"The most important thing is that when he has his time with me, we have quality time together, and when he's with his dad, he has quality time with him," Miranda said. "And it works out really well because I book in my photo shoots for the time he's with his dad, and the rest of the time I just get to be a mom."
Miranda is now happily engaged to Snapchat founder Evan Spiegel, while Orlando is dating Katy Perry.
The model recently opened up about her relationship to the tech mogul, describing him as her "soul mate" in an interview with Paris Match magazine.
"We spend hours talking about everything," she said. "He listens to me and he understands me. He works very hard and he's proud that I've started my own business. He gives me tons of advice. He's my soul mate."