"I know there's a better way to deal with those things than I did," said Heigl. "I could have handled it with more grace."
However, the "27 Dresses" star said she doesn't regret her decision to leave the show.
"I did the right thing for me and for my family but I do regret the heightened drama I was feeling at that time," said Heigl, who moved to Utah with her daughter after she exited the series. "If I'd known anything about meditation then, or had been talking to a therapist or someone to help me through some of the fear that I was steeped in, I think I would have been more calm in how I approached what boundaries I needed to create to thrive."
"I certainly regret not learning earlier how to manage my anxiety better," she continued. "Living at that heightened level of anxiety ... created a defensiveness in me and wariness and assuming that people were against me. I let my mind run rampant without the tools to properly manage that."
Publicly it seemed to start when she withdrew her name from Emmy consideration a year after winning the award while on "Greys."
"I did not feel that I was given the material this season to warrant an Emmy nomination" she said in a statement at the time.
Despite everything that went down, Heigl said she's ultimately "grateful" for her time on the long-running ABC drama, calling it a "really extraordinary experience."
"[It] taught me is that no matter how big an opportunity or how rewarding something is, there will be moments of struggle," she explained to People. "There will be difficulties and disappointment and miscommunications, but you must learn how to manage those with grace instead of fear."
"When I look back on 'Grey's Anatomy,' so much of it was a really extraordinary experience," she added. "It feels like a dream sometimes, all of us in it together like that. I'm grateful for all of it -- and I'm so grateful that I grew up enough to allow it to teach me something."
When asked if she'd ever consider returning to show -- which has been known to bring back characters -- Heigl told People, "never say never."