Strong Smell of Gas/Hydrocarbons in my Car When Parked for A longer Time

What is your question?

I have a Nissan Rogue 2012 which is pre owned. I filled the gas tank and noticed the gas was leaking from under. But it does not drop or leak when the tank is not on full. Also, there is heavy smell of gas or hydrocarbons inside the car each time I park it over night. This makes me to open all doors to vent the car before usage. The smell is surffocating. What might be the cause? I also keep all windows down when driving to air the car which doesn't smell nice. I can't use the AC or heater as the air is always stuffy that I will be forced to put it off and open the windows again.