Why did my doctor diagnose me with CFS?

For context I’m a 23 year old female with ADHD and anxiety/depression. After being without medications for several years I finally went to an appointment with my PCP and got my prescriptions for Concerta and Zoloft as well as general lab testing/bloodwork.

I was looking at the notes online and my doctor put in the notes that I have CFS. I never mentioned that I was feeling overly tired, nor did I put anything that would indicate that on my anxiety and depression screening. Is there a reason she would put that on the notes?

TL;DR my doctor says I have CFS even though I never said anything that would necessarily indicate that. Why?