When I get sick with something, even as benign as a cold, it almost always triggers a flare for me. Anything that triggers our immune systems has the potential to trigger a flare. My flares feel like a horrible case of the flu.
As for work, if you are officially diagnosed, or even if you arent but have a good rheumy, you might want to look into filing FMLA where you work. This will protect your job if you have to be out for any amount of time with your illness, even a few days. And, I have found that employers are much less likely to give you grief about
your illness if you have that on file.
I sure hope you feel better soon!