Coolant light turned on and my engine was smoking?

So, i was driving my car to school and i turned my car off for maybe 20 minutes, then i had to go pick up my friend and 2 minutes in the drive my coolant light came on and my engine was smoking. so, i turned it off, looked under the hood and saw coolant leaking. so, i called my parents i was 2 blocks away from school so i drove it but half way there i turned off my car so it doesn't overheat and after 5 minutes i turned it back on and my coolant light turned off and it stayed stable, and no coolant was leaking. I don’t know what the problem could be.