Get it checked out...do not take no for an answer.
You say that your vision is not affected, so my unqualified guess is that you are not greying out in any sense of the term.
Obviously a BP check should be done, but I would want to be very, very certain that I was not suffering any form of meningitis if I were you.
How is your hearing...and is it symmetrical? Balance in Hi Fi terms.
I am not really sure of the mechanism of what is loosely described as heat stroke, but a pal of mine in the UK was rushed to hospital a while back. He was poorly for quite a while after heat stroke was diagnosed.