The title you see here is an English idiom. Here's the story, see if you can get the idiom's meaning from context.
It all started in Vienna.
When I got home, I got the flu. Oh, was I sick! But I slept and drank juice, herb tea, and Unicum -- and now I am ready to teach again. Teaching is like most jobs: a combination of stress, interesting people, and things to do all the time -- it is "thick" like pudding! So, now I am back in the thick of things.