How do i know i have sun stroke?

Heatstroke: As opposed to heat exhaustion or heat cramps, heatstroke is a very serious medical emergency. It presents with a body temperature of greater than 40.6 °c (105.1 °f). Usually this is from exposure to sun and the bodies inability to thermoregulate this heat exposure. You typically will have altered mentation, dry skin, rapid, strong pulse and dizziness.

Sunny ain't strokey: Heat stroke is probably what you mean by sun stroke. There are brain complications to heat stroke including headache, confusion, seizures and even death. But sun "stroke" doesn't typically cause true stroke which is death of brain tissue due to lack of sufficient blood flow to the brain--unless the heat stroke is quite severe.