Doreen Mann was only rescued after a waitress at the cafe she visits regularly became concerned about not seeing her and raised the alarm.
Mrs Mann, from Southend, Essex, said: “I still can’t believe it happened and thank God I survived.
“I do not know how I did it. I mean I just couldn’t get out of the bath and I was there from Friday morning until Monday morning.
“The peculiar thing was I always hang my dressing gown on the boiler door but this time I hung it on the door which is right by the bath. Because I did I used that as a makeshift cover.
“I had that and the towel.
“It was frightening because I didn’t know how long I’d be stuck there.”
Waitress Sonia Congrave, 39, called the police after the elderly widow didn’t turn up at Cafe Tomassi, in Southend.
She’s been a regular there five days a week for 13 years. When officers arrived at Mrs Mann’s home, they could hear her calling for help.
Mrs Mann said: “We are close, Sonia’s like a daughter to me, as I haven’t got anybody else.
“She’s getting me a mobile phone now because of me being upset in the bath all those days.”
Ms Congrave, a mother-of-two from Southend, said: “Doreen said she wasn’t sure she was going to make it.
“She said she drank the water from the tap and kept filling the bath and letting it out until she stopped and covered herself with a towel and robe.
“She is a really strong woman – all she wanted afterwards was her cake and a cup of tea.”