Flu? Not covid

Hey guys… is the flu going around or something else Besides covid?

My manager is sick with a fever for one day, had body aches and a cough. I know sounds similar to covid but she’s taken 5 tests and all negative. She also had symptoms Sunday and I worked with her today (so about 4 days after she had sick symptoms) Sometimes we were in a close proximity today but I had my mask on If that helps. I just had covid 2 weeks ago and finally tested negative. Should I be concerned of catching whatever she has even tho I wore my mask and it’s been a few days after she became sick? Lmk what you guys think