Lady Gaga responded to the criticism with the lengthy post on Instagram.

“As I get stronger and when I feel ready, I will tell my story in more depth, and plan to take this on strongly so I can not only raise awareness, but expand research for others who suffer as I do,” she wrote.

“I use the word ‘suffer’ not for pity, or attention, and have been disappointed to see people online suggest that I'm being dramatic, making this up, or playing the victim to get out of touring. If you knew me, you would know this couldn't be further from the truth. I'm a fighter. I use the word suffer not only because trauma and chronic pain have changed my life, but because they are keeping me from living a normal life. They are also keeping me from what I love the most in the world: performing for my fans.”

The Live Nation statement said Lady Gaga would “spend the next seven weeks proactively working with her doctors.”

The singer's European concerts were scheduled to begin Thursday in Barcelona, Spain and run through the end of October. Fans were told to keep their tickets until the concerts were rescheduled. Lady Gaga is still scheduled to perform during the second leg of her North American tour, which begins November 5 in Indianapolis.

Fibromyalgia is a poorly understood disorder characterized by deep tissue pain, fatigue, depression and insomnia. As many as 90 percent of fibromyalgia cases are diagnosed in women.

Lady Gaga also has chronic hip pain from synovitis, an inflammation of the joint that can be caused by overuse or injury. Her struggle with chronic pain reportedly began over a decade ago with physical and emotional trauma caused by a sexual assault.

“I have always been honest about my physical and mental health struggles. Searching for years to get to the bottom of them. It is complicated and difficult to explain, and we are trying to figure it out,” Lady Gaga wrote on Instagram.

“I am looking forward to touring again soon, but I have to be with my doctors right now so I can be strong and perform for you all for the next 60 years or more. I love you so much.”