The 46-year-old actress shared a photo from one of her early chemotherapy sessions Friday for Breast Cancer Awareness Month, which takes place in October.
"Breast Cancer Awareness month continues. This photo represents so much of my journey with chemo," Doherty wrote.
"I had completed my first chemotherapy session. Was on steroids and yet so sick. Bloated yet throwing up. I had to be hooked up to get hydrated because I couldn't keep even water down."
"Chemo is different for everyone. Some tolerate it better than others. At the time, I remember thinking it couldn't get much worse," she recalled. "I was wrong. Yet I am here today. A different person than I was."
"I don't think I've yet discovered all the ways cancer changed me. As I told someone recently..... I am a work in progress and I'm ok with that. #sutc #breastcancerawareness," the star added.
Doherty posted a "personal" image earlier this month of herself breaking down after starting chemotherapy.
She recalled how she felt like she was "losing" herself as she started to lose her hair from the treatments.
"Cancer has so many phases. Shock, denial, acceptance, anger, resentment, rebellion, fear, appreciation, beauty. Remission. Even then, the phases keep coming," the star shared. "Cancer is with you forever."
"Those who have experienced it know that even after you've kicked its [expletive], it still impacts you," she added.
"You still go thru the roller coaster of emotions. You still need support and love. And you can still grasp life and live, live, live."
Doherty announced in April that she's in remission after being diagnosed with breast cancer in March 2015.
She said at the time that she will remain on medication and undergo reconstructive surgery on her breasts.
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