Use a different Firefox profile for work/personal.
Sign-in to personal (while at work) to sync bookmarks if firewall allows. Depending on whether you trust your employer you could sync further personal settings.
Don't sign-in to work profile and no work bookmarks or settings/logins get shared.
Don't get me wrong: multi-account containers are a blessing for those rare days when you absolutely have to log-in to facebook.
Used to experience the same. Eventually had tonsils and adenoids out. Some improvement in frequency, but still used to succumb. Went low-carb (properly) and found myself without _any_ congestion, which solved the initial and subsequent problems. N=1, etc. One paper by Paton from 50's relevant (re pneumonia), otherwise nothing I can find in the lit. Recommended, though, for that and other readily apparent reasons.