What is the year that became known as the Year of Sorrow in the life of the Prophet, peace and blessings be upon him, and what were the events that made it so, and what was the Prophet’s reaction to them, and what are the lessons learned?

The year in which Khadijah and Abu Talib passed away became widely known as "the Year of Sorrow" due to the profound grief and harm that befell the Prophet, peace and blessings be upon him, after their deaths. This occurred three years before the Hijra. However, it has not been established that the Prophet, peace and blessings be upon him, or any of the early Muslims (Salaf) named this year "the Year of Sorrow." Rather, it is a designation given by scholars, and it has not been narrated with a chain of transmission (musnad). Some narrations that attribute this naming to the Prophet are accused of being fabricated. It is unlikely that the Prophet, peace and blessings be upon him, would have named it as such, as he experienced greater hardships and trials that he did not designate with names indicating sorrow.