I would just tell the truth.

By the way, that yellow sheet on your car would not show any information for how long you have stayed in US. It was merely a sheet like a "parking permit" to let you pull over your car, and go to the immigration office. After you finished all your "deal" with the immigration officer, you needed to hand in that yellow sheet to a police, then pick up your car. I had the same experience at Niagra Fall.