Antifreeze leak

I have a 1995 GMC Jimmy, it is the down-szie version.

4.3 L engine and 4WD.

I was driving down the highway when the check gauges light came on. I noticed that the temperature gauge was very high, even in the red sometimes. I tried turning on the heater to cool the engine, but there was very little heat coming out. When I got home I opened the hood looking for a leak. There was no coolant in the overflow tank and no hoses leaking. I looking underneath the car and the bottom of my car had antifreeze on it. Most of it was on the front differential for the 4WD, but there were parts of the frame with antifreeze too. I have not checked the radiator level yet because the engine is still hot.
I'm thinking that it may be the water pump, but I can see if there is any coolant leaking from this.
I am going to make an appointment with my mechanic, but I was hoping to get your opinion first