[Bearfootfarm]

What needs to be fixed?

The part that's leaking, although without air in the tank your pump should be running, trying to keep up the pressure setting.

You'll need to shut everything off, drain the pressure tank, repair the leak and then refill with air to a pressure about 2 lbs less than the lower setting on your pressure control switch.

 

[Bearfootfarm]

Is there a chance that the freezing weather this morning caused a seal or something to be loose?

Freezing weather can cause lots of problems, but it shouldn't.
Put a heat source of some type in your pump house.
A single light bulb can make all the difference.