Welcome to HCM
We understand your concerns
I went through your description. You were climbing stairs of a 6 storrey bulding ith lugguage and after that ykou felt nauseous and had urge to vomit. But you did not. You did not mention your age and other medical conditions, if any, through.
Feeling nauseous after heavy work do happen to people above the age of 40. There are so many causes. Immeadiately after food, if you work hard, you are bound to vomit. Tiredness
without enough hydrating agents causes nausea
To exactly ascertain what caused your problem, you might consult a general physician and check your vitals like BP and sugar etc. GP should be able to clrify your doubts. Meanwhile don't worry too much.
Hope I am able to clarify your doubt partially. I am available for further queries.