Ask your environmental service department exactly what agents they are using to control the rats/mice problem, or, if they deny that, what cleaning/disinfecting/exterminating agents have been used in the last 2 months. You have the right to know, since you are breathing it in. When you get the list, research it and see if anything could cause your problems. Good luck and God bless!
It's probably an allergy to work. I get this all the time.