Last year, Errani, who was once ranked fourth in the world, tested positive for the banned drug letrozole, a substance used by her mother for the treatment of breast cancer.
The Court of Arbitration for Sport
accepted traces of the drug found its way into food being prepared for a family meal, but said in a statement Errani was still guilty of a "light degree of fault."
Now ranked 72nd, the 31-year-old says
the matter has been handled in a shameful manner.
"I have dedicated my life to this sport and I don't think I deserve all this," the 2012 French Open finalist posted on Twitter
"The TAS in Lausanne has reconfirmed, once again, it has been an inadvertent ingestion, and moreover, of a substance that is not enhancing performance.
"I have already served seven months. Between results disqualification and period of inactivity, I have been forced to re-start with a ranking position of 280, and I climbed back. And now they want to add an extra sanction of eight months. All of this is total nonsense!"
The decision follows Errani's appeal against the original ban and voided results, while the Italian anti-doping agency had asked for a longer suspension.
According to the World Anti-Doping Agency
, letrozole is an aromatase inhibitor that can act as a hormonal and metabolic stimulant by increasing testosterone concentration.
Errani, who has won five grand slam doubles titles, is unsure whether she has a future in tennis.
"I don't know if I will be able to find the strength and the desire to play tennis again after all of this," she wrote.
Last week, Errani withdrew from the Croatia Bol Open after reaching the semi-final stage.