I THINK MY GUINEA PIG JUST HAD A HEAT STROKE!!?!?

my guinea pig was outside and when i picked her up she was acting very calm....which isnt normal for her cus she like to chew on my towel. she was putting her head against my arm and i looked down and it was wet. but idk what it was from. she is laying down, able to move, but not doing much movement.....i am not able to take her to a vet so i need to know what to do.... plz help!