Whats the best way to keep from freezing to death when you dont have heat in your house?

Bundle up. Your body is a metabolic furnace that loses the heat it makes to the environment. If you bundle (lots of clothing+ blankets) you can prevent heat loss & retain much of what you produce. There are specific heat retaining blankets available at survivalist stores but bundling with what's available at home may do. Many communities open warming centers when severe cold is predicted.

Getting help from the local fire department or seeking shelter through the local hospital are couple of options among many others.