06/12/2012 at 07:30 AM EDT
Chipper, energetic and visibly grateful, Robin Roberts returned to Good Morning America
Tuesday, a day after revealing she is battling MDS, or myelodysplastic syndrome
, a rare disease of the blood and bone marrow – and that she will have a bone-marrow transplant, with her sister, Sally-Ann Roberts, as a donor.
"I slept like a baby for the first time since my diagnosis," Roberts, 51, said at the top of the show Tuesday. She also expressed her thanks for the outpouring of "comfort and support" she's received from viewers, along with all the advice that has been dispensed and that she's been finding helpful, she said.
In addition, she also heard from First Lady Michelle Obama
and Ann Romney, the wife of the presumptive Republican Presidential nominee, Mitt Romney.
"Barack and I have you in our prayers. We believe in you and thank you for bringing awareness and hope to others. –mo," Mrs. Obama Tweeted
Roberts said that she and Mrs. Romney, "who has had her own health challenges … had a lovely conversation" Monday. (Romney has battled multiple sclerosis.) Roberts expressed her gratitude to both women.
On Tuesday, with ABC News chief health and medical editor Dr. Richard Besser, Roberts discussed the possibility that this new setback may be the result of the treatments she received while successfully fighting breast cancer
five years ago. Roberts said she is aware of that link but has no regrets, as it was imperative that she treat her primary condition.
Roberts hopes that the attention paid to her diagnosis will encourage people to donate bone marrow in order to help others with the disease. Her new round of chemotherapy is scheduled to begin immediately, with her transplant to take place in the fall.
"I am very fortunate to have a sister who is an excellent match, and this greatly improves my chances for a cure," she said Monday.
On Tuesday, Roberts once again thanked the public for its love.