I know this is a late comment, but did you take an antibiotic for your sinus infection? There are several that cause the side effects you've described. They are Cipro, Levaquin, and Avelox. This is known as fluoroquinolone toxicity syndrome because this class of drugs is known as fluoroquinolones. There's a film called Certain Adverse Events that describes the stories of people in similar situations. And there are several online support groups. I wish you good health and healing.
Hi and welcome to MedHelp
Yes, you can "one day" get sick with something like lupus. I was outside dragging trees to a pile for the logging truck to load and all of a sudden I felt like the wind left my sail. I thought I had just over did myself and would just need to lay down for about 30 min. A year and a half later, I was dx w/ lupus. I was so extremely sick.
Low B-12 can cause nerve damage, muscle pain, fatigue.
Have they checked you vit D level. That is usually low in autoimmune diseases for some reason.
Have they checked you ANA, RA?
Be sure and spend time in the sun prior to your ANA being checked, if you have lupus, it will cause the ANA to be elevated.
Lupus is really hard to dx. Drs. are very careful to not pass down a wrong dx. It seems once it is put on your record, you can't get life insurance. So this could be a long road to a dx. Be patient. They just want to be thorough. Many times a dx of fibromyalgia is made first. Which is not uncommon in other severe illnesses. So did get distracted by that. Stress seems to trigger lupus flares, so does being in the sun. So try to avoid those things.
I take you've been nauseous or have diarrhea.
God bless, praying for you.
Kara