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.