Sheri Shermeyer posted the lengthy note at around 11am on Boxing Day, writing: "All I can think about is leaving this world. Putting a gun in my mouth and leaving. Which is what is about to happen."
Three hours later police in Pennsylvania, USA found the mum and child dead at her home in Shrewsbury Township.
The New York Daily News reports police confirmed Sheri was found dead from a self-inflicted gunshot wound and one-year-old John Shermeyer had been suffocated by his mother.
The chilling Facebook post, which appears to be directed at her child’s father, went on to detail the love she feels for her son as well as the challenges she’s faced “as a single parent in a 2 parent home.
Shermeyer, who married Tracy Alan Shermeyer in October 2014, appears to indirectly address her partner in the message.
“You will never see your son again,” she wrote. “You don’t deserve to have a son, a legacy. Why should you have your name carried on? You are a nasty man.”
Shermeyer ended her Facebook note by calling her son’s father as a “stumbling drunk” and “an a--hole who deserves to be alone.”
She added: "Oh before I get forget. Make sure you take mine and John’s life insurance and pay off my debts. Enjoy your miserable life. Thanks for saying good bye when you left this morning.”
Shermeyer’s death is being investigated as a suicide and her toddler’s as a homicide.