World number two Rafael Nadal feared a persistent foot injury would force him to quit tennis at the age of 19.
"I have cried many times at home especially when I saw that I couldn't play and the pain wouldn't go away.
"I would leave it a few days and try again but the pain would come back. It was a really bad time."
Nadal injured his left foot while preparing for the Masters Cup in Shanghai in November, and has not played a competitive match since winning the Madrid Masters in October.
The French Open champion played an exhibition match in Tarbes, France, on Sunday where he beat Fabrice Santoro 6-2 1-6 10-3, the third set being a super tiebreak format.
He will miss Spain's Davis Cup tie against Belarus this weekend and is scheduled to begin his season at the ATP event in Marseille starting on Feb.13.
"I am pleased that we have located the problem and have now taken measures to solve it," Nadal said.
"They have made new soles for my shoes and changed the supports for my foot and that seems to be working because I don't have the same kind of pain as before.
"I am still a little worried but that is only normal. That won't disappear until I have played a few tournaments."
When asked about whether he would change his aggressive, hard-running style Nadal said: "I will try to be more economical with my effort when playing but everyone has their own style and you can't change that."