Ahead of the 40th anniversary of the beginning of the war on April 2, Ms Davidson, 65, spoke for the first time about losing her husband and the importance of remembering all those who served.
A total of 255 British servicemen, 649 Argentine military personnel and three civilians were killed, while many more were wounded.
Lance Sergeant Mitchell was one of eight Scots Guards killed in the Battle of Mount Tumbledown in the early hours of June 14.
Ms Davidson said she remembers receiving the news “as if it were yesterday”.
“When he was away, I had this dreadful fear, and just lived for the news,” she said.
"On the morning of the 14th I felt so happy and thought ‘Thank God the war is over’. But then it was like something had hit me, and I knew something had happened to Clark.”
She added: “I remember it as if it were yesterday. I was in our quarters at Lasswade, Midlothian, when an officer and his wife came to the door to tell me the news. My world just fell apart. I lost everything: my husband, my best friend, the family we wanted together.”
Ms Davidson, now a foster carer, had met her husband, who was from Laurencekirk in Aberdeenshire, at the age of 17 when she was training with the Women’s Royal Army Corps.
After six years of married life in Germany and England, they had returned to Scotland and were hoping to start a family when the conflict began.
“Losing Clark changed me, and it took me years to rebuild my life,” she said.
"He was an extremely good soldier, but he was also very gentle, kind and caring, with a great sense of humour and zest for life. I will never forget him or the sacrifices he and the other men made. To me it’s about keeping their memories alive.”
Military charities Legion Scotland and Poppyscotland have launched a programme of events to commemorate the conflict, in partnership with the Armed Forces and the Scottish Government.
These will culminate in a national parade and remembrance service on June 18 in Edinburgh.
Dr Claire Armstrong, Chief Executive of Legion Scotland said: “The Falklands conflict was the first military action since the Second World War which involved all elements of the Armed Forces.
"Although it lasted just 74 days, it claimed the lives of hundreds of servicemen and had a lasting impact on thousands more, as well as their families. Many veterans still struggle with physical or mental scars, or have faced hardships in the years afterwards.”
Mark Collins, Interim Chief Executive of Poppyscotland, said: “We want to remember the extraordinary efforts of thousands of service personnel, the civilians who played a vital role, as well as their families. This is also a chance for people of all ages to learn more about the Falklands conflict and how it has shaped our recent history."