Recovering from thyroid cancer. Have interviewed at a few places and have been unsure what to say in the application. Also, have been insanely tired and unable

Recovering from thyroid cancer. Have interviewed at a few places and have been unsure what to say in the application. Also, have been insanely tired and unable to deal with the stress of interviews. The prospective employer didn't know about my situation. I completely tapped out in one of the interviews and was unable to focus but to the interviewer, I probably appeared like I struggled to answer their question. It's been life changing going through this.