Serena Williams is "at the end of (her) rope" after several physical setbacks that have kept her off the court since July.
"It's just been a tough year," the 29-year-old in an interview published in USA Today.
Shortly after her fourth Wimbledon title, Williams cut her foot on some broken glass at a restaurant resulting in a pair of surgeries.
"I definitely have not been happy," she told the newspaper. "Especially when I had that second surgery (on my foot), I was definitely depressed. I cried all the time. I was miserable to be around."
Then last month, she suffered a pulmonary embolism and was hospitalized to remove a grapefruit-sized hemotoma from her stomach.
During her time away, Williams has fallen to No. 11 in the rankings.
"What's going to make me happy is going on the court and holding up trophies, singles and doubles," she said.
She has not set a timetable for her return to tennis but said it could come as early as this summer.
"I don't know what's realistic," Williams said. "I really don't know. I haven't put a date on it yet."
