"My plan was to come here and run the marathon, win it and then decide after that. It is not a decision I am going to make in the next 24 hours. Emotionally and physically I need time to make a decision.
"Part of me wants to do it but I can't do it if I'm not right. But I will be back definitely. I will pick myself up and I will be back."
Radcliffe saw doctors in Athens to undergo a series of tests and is awaiting the results this evening. Any medical problem is certain to signal the end of her Olympics.
She added: "I am struggling to comprehend what happened and find a reason for it. The conditions were tough for everyone and I prepared for the conditions and I don't think the heat was a factor.
"I got to the stage in the middle of the race when there was nothing in my legs. I am totally devastated because this race was what it was all about and I was preparing for this."
After her tearful TV interview, Radcliffe faced a barrage of questions and flashbulbs at a media conference.
Radcliffe said: "Physically, I feel fine. My legs maybe felt they hit the ground harder than they did but physically I am okay. Mentally I am trying to pick up the pieces.
"It's really difficult. I didn't feel the conditions were excessively bothering me heatwise but after 15-20km I felt nothing in my legs. I felt I could regroup but in the end I was struggling to stay on the road and I felt numb."
