At about the 5:55 to 6:05 time in the video "Critical Care Unit to Hospital Ward *cancer*, Tiffany gives the indication that day 4 in the critical care unit is a Monday. From about 5:55 to 6:05, she says "because I've been here for a long time". Then, she mumbles as she seemingly reviews the days she has been in the hospital, ending with 'Monday (at about the 6:02 time) --4 days in here.' Apparently, she was mentally reviewing the days from Thursday, Dec. 15, to Monday. Inclusive of Monday, she would have been in the critical care unit for four days (Friday, Saturday, Sunday, and Monday), and this was her forth day, which, as per the manner in which she was counting the days, clearly enough ended with 'Monday' under her breath.
As indicated months ago with the disappearing date of Dec. 15 (Someone had written that date in her one of her comments sections months ago, and it was quickly deleted.), that date was most likely her surgery date.