The whole of it
It begins in the body. In time, it reaches everything.
It usually begins with symptoms that are entirely physical. As they carry on, and no one can yet say why, their reach widens. Energy that once went into work, family and friends goes into getting through the day. Doing less can mean feeling worse, and feeling worse can mean doing less, until it is hard to tell where one ends and the other begins.
Many of the people we meet once had full, demanding lives: careers they had built, families they cared for, plans they were making. Losing so much of that, without an explanation, is a grief of its own. When low mood or worry follow, as they so often do, the symptoms themselves can come to be put down to them, rather than to a physical cause still waiting to be found.
This is what a long, unexplained illness can do. It deserves to be understood, and so do you.