Over-heating I've been putting anti-freeze and noticed it is leaking out

Hello,

An engine can overheat due to low coolant level as well as several other factors like a stuck closed thermostat, bad water pump, faulty radiator, issue with the cooling fan etc.
Since you are experiencing leak, the first step would be to inspect and determine where the leak is coming from and repair.
Coolant can leak from the radiator, any of the hoses, water pump gasket, thermostat housing etc.

Here is a helpful guide that goes over what to look for:

https://www.2carpros.com/articles/car-is-leaking-coolant

The gauge on the dash could be simply reacting to the overhearing of the engine.

Let me know your findings.
Thank you.