Is it all in my mind?

No. Neither is it all in your gut or even your body. IBS is a condition that affects both your mind and your body and defined by the Bristish society of Gastroenterology as ' .....a disorder of gut-brain interaction, rather than a functional gastrointestinal disorder.....' . 

But changes in gut immunology or the bacterial content of the colon can affect the way you feel and the symptoms of IBS can make you anxious, depressed and desperate. IBS is a vicious cycle that affects both the mind and body.