You want a heavy fleece blanket plus a regular comforter. If you can afford to get yourself a heated blanket you will be living in the lap of luxury.

This is kind of living situation dependant but, if you find that your windows are drafty blackout curtains are a decent insulator if you can't put up something more serious.

If you can't control the heat of your whole living space (someone else controls the thermometer and you're cold, or maybe your room is a cold spot) you can keep the heat in your bedroom by covering up your windows and the top part of the door with a blanket. I'd do this before getting a space heater.

Go buy a case of ramen and a bottle of your favorite eye watering hot sauce. Sometimes you just want to clear out the face pipes.

Make a little winter survival kit for your car. https://www.skilledsurvival.com/winter-emergency-vehicle-kit/ This list is super intense but it's not bad. I wouldn't be too worried about like... a propane heater, camp stove or a gas tank. My SO swears by traction mats, but if they won't fit in your car you can throw down some sand or kitty litter under stuck tires.

Oh, don't' forget to drink water and use chapstick