Heather B. Armstrong was never a mommy blogger who presented an idyllic picture of parenthood. Her Dooce.com — which began in 2001 — is full of candid posts about her postpartum depression, divorce and struggles as a single mother.

But in 2016, Armstrong reached a nadir: She woke up every day wishing she were dead.

“I had this demon in my head saying, ‘You’re never going to feel better,’ ” the 43-year-old told The Post.

So she decided to take part in a clinical trial that would temporarily leave her brain-dead — 10 times.

That experience is the subject of her book “The Valedictorian of Being Dead: The True Story of Dying Ten Times in Order to Live,” out Tuesday. In it, Armstrong details her brutal 18 months of treatment-resistant depression, as well as the medical experiment, in which doctors used propofol anesthesia to flatline her brain ­activity for 15 minutes.

Armstrong, a Salt Lake City resident, has suffered depression since high school and had her first nervous breakdown while at Brigham Young University. After she gave birth to her daughter Leta 15 years ago, she checked herself into a psych ward for postpartum depression. (She also has daughter Marlo, 9.)

Yet the 18 months before she began the clinical trial were the worst she had ever experienced. It started in 2015, when she signed up to run a marathon. The intense training proved too much, with travels, work and family. Armstrong felt so overwhelmed that she stopped showering and brushing her hair. She also stopped taking her medications, which weren’t working. Keep reading…