Why do i get hot so easily?

I get hot so fast and i feel like im going to pass out.i live where its very hot all the time.but i dont think i should overheat that fast.if i go outside for 10 minutes ill start feeling sick.i dont sweat alot or anything so thats not a problem.i just dont understand why i get so hot and sick so fast.
help?
Update: i never said that i dont sweat at all...i just said i dont sweat alot!
and all i drink it water.so its not that.
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