Robin Roberts: "My body is so weak, but not my mind"

(CBS News) Robin Roberts is giving fans an inside glimpse into her treatment, leading up to her bone marrow transplant on Thursday.

The "Good Morning America" anchor has been updating her blog, and in her latest entry, Roberts, 51, writes, "The start of last week went well, but the daily chemo/treatment caught up to me by the weekend. My body is so weak, but not my mind. YOU give me the courage to keep going."

Roberts is battling myelodysplastic syndrome and will receive a transplant from her sister, Sally-Ann. Tuesday marked Roberts' last day of chemotherapy prior to the transplant.

It's been a stressful couple of weeks for Roberts, who also lost her 88-year-old mother, Lucimarian Tolliver Roberts, last month. According to her Facebook page, Roberts traveled "home to Mississippi just in time to see her."

"Last Sunday to lift my spirits I threw a little party at my apartment for my 'GMA' family," Roberts wrote on Tuesday. "The next morning I walked through the hospital doors, with my guardian angels -- mom & dad -- back together and blazing a trail ahead of me."

Roberts left "GMA" on an extended medical leave Aug. 30.

There's no timetable for when Roberts will be back at "GMA," but she said she'll return "as soon as I can."