I absolutely agree with previous replay. First of all, I am sorry you have to be in this situation, but trust me, most of us been there -done that.
I worked in a very though field, financial institution with millions of $$$ involved (trading) and was only woman in the office with 30 "sharks". To swim in this type of pond is never easy, but when you are chronically seriously ill, takes a lot of you to look great, to be professional and to never show to anyone your pain or your fever is high.
We had gym in the office and everyone exercised every single day there, so did I. I would use knees braces b/c I had multi knees surgeries and was in constant pain. RA left them bone-on-bone. I wold be embarrassed not to go to the gym, I didn't want them to think I cant do that. Are you kidding me?
I am pretty sure all of my guys would be very shocked to find out what demons I fought every single day. But they never heard me complaining or sharing with them my health issues, never.
First of all, it's not professional, nobody's business, fear of loosing my job, and I guess pride?
I can hear in your letter that you are smart and ambitious person - great for you! You want to achieve something big in your life, so do it! You dont have to explain to anyone why you tired or why you absent that day. We all have rights to privacy, so use it. I think your administration may need to know, otherwise they may get wrong ideas why cant you keep up with every day work. Pick a person who you trust (don't you have a counselor?) and explain your situation. This way you will feel so much better knowing that nobody judging you for being absent or not doing your work like everyone else.
Rather than that - just forget it! Don't explain yourself, don't worry about someone noticing anything. Trust me, nobody probably even cares, but in your conscious mind you worry, and all for nothing.
After all, pay attention to your health, to what you see in front of your future and to people who love you and who you love.
Rest of it, don't even matter.
Best of luck to you sweet heart,