Heartbreaking.

Sarah Mandel, who worked as a psychologist and author, passed away earlier this month after a brutal seven-year battle with breast cancer.

Mandel, who documented her fight with the deadly disease, uploaded a final video to TikTok letting her followers know that she had died.

In the post, Mandel writes: "If you're reading these words right now, then I have died. I wrote this message the week I was told I had weeks to months to live."

During the two-minute video, Mandel reflects on her life and her death, sharing a number of clips showing her taking part in different activities with her family.

She added that she never expected she would "announce her own death on social media" but later decided to as the support she had received over the years had helped her throughout the battle.

She said: "Life is unpredictable and full of surprises. The support I found on this platform helped me face the toughest days of this cancer ordeal.

"It's no joke. We need people to help us. My heart felt like it grew exponentially from the care I received from old friends, new friends, and strangers.

"Thank you for holding my hand throughout this one example of a challenging life story. We all have our versions. We all need our hand held sometimes."

She added: "I am heartbroken that I am leaving this life well before my plans. Most of all because of my girls and my beloved Derek.

"I'll write it here, and if I could, I'd write it everywhere. Sophie and Siena, I love you and I am so proud of you. I may be somewhere beyond our concepts of infinity now, that's how much I love you."

Her husband Derek later revealed that he had no idea she was going to schedule the video to be posted after he death, saying that he was "completely shocked".

Sarah's family added that she "died peacefully in her sleep" and was "thankfully very calm and comfortable in her final days".

So heartbreaking.