Hi Stephen,

You said it yourself that you've been exhausted at times. You could always explain to your friends that you're simply exhausted. You could tell them you're thinking of getting a good medical workup done.

From my own experience, I'd never reveal some of the things I did to my coworkers, if I could do it all over again. It's not a live or die decision, and you have time on your side to consider the best course of action. Whatever your decision is I hope it works out well for you.