Temp spike, and quick RPM reduction (06 Aveo)

[BBruins12]

Desperate need of an oil change means I'm WAY over 3K/3 months to the point that I don't even know how over.

There isn't a leak anywhere that I can see. I looked where my car was parked when I came back to the driveway, but all that had been there was the condensation from the AC Unit (which I noticed when I left), that had evaporated by the time I got back to the driveway.

Edit:
The Timing belt was done in August, as well as the valve cover gasket, the plugs and wires, and the thermostat/housing

I'm going to bring it back to the guy who did my timing belt to have him check the tension.

As said in my original post: "The hose running from the thermostat to the radiator gets rock hard, and hot when this happens."

It's like someone inflated it (like a ball)... which makes me think it IS the thermostat...so you see why I'm torn.