(CNN) -- Outgoing Secretary of State Hillary Clinton says she's "thrilled to be back" after an illness, concussion and treatment for a blood clot sidelined her for more than three weeks.
Clinton returned to work Monday and made her first public appearance Wednesday morning. She was released from a New York hospital last week after three days of treatment for a blood clot between her skull and brain.
"I am thrilled to be back, and I am also incredibly grateful to this fabulous team that I have here at the State Department, who never missed a beat for the time that I was away," Clinton said.
President Barack Obama has nominated Massachusetts Sen. John Kerry to replace Clinton, who is staying on until her successor is confirmed by the Senate. She said she is "back in the swing" and focused on preparing "a very smooth, seamless transition."
Clinton's health woes began with a stomach virus in mid-December. The State Department said she fell and hit her head while suffering from dehydration, leading to a concussion. Then doctors found the blood clot during a follow-up exam, leading to her admission to New York Presbyterian Hospital on December 30.
State Department staffers presented her with a welcome-back gift upon her return to work Monday: a football helmet.