Hi, Welcome to Health care magic forum.
As you describe, it appears to be the
heat stroke, due to the sun. Sun burn is different it is a chronic effect, due to continuous exposure to the sun for many days.
I advise you to consult a physician for diagnosis and treatment .
As a preventive measure you can use anti emetic before going to the sun.
Other wise you can have anti emetic after returning from the sun.
Take more of water and liquids so that you don't have the heat stroke.
Take more of green leafy vegetables, pulses, sprouts, and protein rich foods,to have good health, recovery, and resistance.
Wishing for a quick and complete recovery. Thank you.