PG&E Bill Insane

HELP! My PG&E Bill has been greater than $600 the last three months. Heater is run by gas. I’m diligent about keeping thermostat at or below 65 degrees and we keep lights off when not in use. We had insulation in attic installed when we bought this time last year. We’ve debated installing solar but the cost is so high. SF ~1400 sq feet in East Bay. Any advice appreciated.