We been having cold weather. The low temperature is in single digits. I am thinking the water line might be frozen. I do not have a crawl space under the house because my home is on a concrete base.
It may kind of depend on where your water source comes in at before it enters the water heater whether it's frozen or not. Before calling a plumber, make sure that all the intake valves are open. Also it is possible that the tank is full of sediment. Maybe have a friend or family member come to check a few things before calling a plumber would save you a little. It may be a simple fix.
You could have a frozen line or pipe. You will have to call a plumber