What Causes Constant Sweating?

Hi Im a 23 yr old female that is 4'10 130 lbs. why am i always hot? i sweat all the time because of it. i've had this problem ever since i was 14. i've seen a doctor but they say i will grow out of it. but its gotten worse, i can barely sleep at night, and then when i do, i wake up in the middle of the night pouring sweat and i feel like someone put me in a furnace. i have to lay on the floor near the a/c vent and it takes me hours to cool down. please help me