Ariel Winter is getting candid about the difficult time she went through before undergoing a breast reduction surgery last June.

The 18-year-old "Modern Family" star wrote an essay for Motto, a website from the editors of Time, in which she describes just how much her former 32F bra size was hurting her both physically and psychologically. Winter revealed that her body unexpectedly changed dramatically over the course of one summer.

"I came back to film season 3 of "Modern Family," and I knew that I looked totally different than when we’d wrapped season 2," she recalled. "Suddenly, I was just over 5 feet tall and was an F-cup."

WATCH: Ariel Winter Defends Not Hiding Her Breast Reduction Surgery Scars at the SAG Awards

"Women are already over-sexualized, and I grew into my body so young," she continued. "I was 13, 14 years old, and I looked 19. Suddenly, people didn’t want to talk about my job -- they just wanted to talk about my cleavage."

Winter received plenty of unwanted attention online.

"I'd go to awards shows and the next day see everyone on the Internet telling me I shouldn’t look like this and dress like that," she wrote. "The conversation became about my looks instead of my talent and work -- everything that I didn't want. I even started getting messages from older male fans, and let's just say they were gross."

Of course, her issues were more than psychological.

"It's really difficult to be such a small girl and have so much weight on your chest," Winter explained. "You physically hurt. You can't find clothes that fit right. I couldn't find a cute bathing suit. Everything looked like I was trying to be 'sexy.' It didn't help that I didn't look like any of my friends my age."

"I was uncomfortable and unhappy," she stressed. "I chose surgery because of how I felt, not because of what anyone else thought."

After going from a 32F bra size to a 34D post-surgery, Winter said that she began to feel the positive effects of the procedure immediately. Clearly, she doesn't regret her decision one bit.

"Don't get me wrong: I don’t think women should ever change themselves based on anyone else’s standards," she wrote. "My surgery got a lot of criticism from some people, but I'm happier for it. In the end, I think it's all about how you feel --- not what other people think."

When ET caught up with the actress last October, she echoed that the surgery was more about her own feelings, than the online bullying she was being subjected to.

"I mainly did it for myself," Winter said at the Teen Vogue Young Hollywood party in Beverly Hills, California. "Yes, I had many comments, and it bothered me that that was kind of what I was known for. And that was kind of what people were commenting on my photos. That bothered me, but it wasn't the main reason I did it."

"I just feel so amazing with all the support I've received," she added. "It's been a wonderful year for me."

WATCH: Ariel Winter Opens Up About Her Breast Reduction Surgery -- ' I Just Feel So Amazing'

These days, Winter is more confident and gorgeous than ever. The actress stunned in a strapless black Romona Keveza gown at the Screen Actors Guild Awards last month, and notably, left her new scars from her surgery visible.

"Guys there is a reason I didn't make an effort to cover up my scars! They are part of me and I'm not ashamed of them at all. :)" Winter later tweeted about her much-lauded decision.