Code P0128, possibly related to over filling Freon, or no?

The A/C was blowing hot. Condenser pulley engaged. Added 32oz can of Freon to low side. The needle on gauge was dropping as I was adding it. Would go from low to good then back to low. Added whole can. Seemed to sit in the green steady after that. Blew cold for couple minutes. Then turned truck off. A week later I needed A/C. No A/C. But. Thought maybe I did something wrong and overfilled freon. No signs of freon leakage under truck on pavement. Fast forward to mid road trip today another week later. Used heater. Shortly after the fan was stuck on high. Don't think it was related to using the heater. But maybe? Engine temperature not reading on gauge. Threw code 0128. From my knowledge that means coolant pressure sensor or thermostat needs to be replaced. What I'm wondering is did I add too much Freon? Can freon overcharge result in failed thermostat or is it a separate system that doesn't affect each other?