I’m so sorry. This sort of sounds like a low-grade* viral infection, but it sure is lingering a long time.
*low-grade meaning not crazy symptoms of high fever, violent nausea/ vomiting/ diarrhea, etc. But it’s certainly miserable as is!
You’re right, specific exercises don’t do anything for immunity, although general exercise and fitness activities like walking around the block do help your overall health. Your best bet is to eat sensibly, hydrate-hydrate-hydrate until your pee is completely clear and keep it that way, get some general exercise as mentioned above, and just generally practice some self-love. I haven’t been around here long, so I don’t know your story, but if you’re biologically female, are your menstrual periods regular? Mine were all over the place in my younger days, and that definitely affected my wellbeing.
If it doesn’t clear up in another week, I’d go back to your doctor. If she blows you off, think about getting a new doctor. Be careful with the Pedialyte - there can be such a thing as too much of a good thing. You don’t want your electrolytes to get out of balance, because that can cause some of your symptoms (not saying that’s it, but it can be a “confusing factor.”
And your chicks are darling! I started chickening with 7.5 week old pullets, which was the right decision for us, but these pics of baby fluffballs do make me jealous!
Edit to add: I don’t want to get nosy about your private health, but I did want to mention that I hope your doctor did pull blood for lab work, including fasting blood glucose and HgA1C (sometimes called an A1C test or glycated hemoglobin test.) Having well-controlled blood glucose (blood sugar) is incredibly important for your health and well-being.
checking to see if she makes it or not. What brave boys 
