回复：ambulance made a U-turn, you followed it

These guys are so mean. It was not fully your fault, most new drivers might have the same confusion. In that situation,  the best way is to get away the scene as far as possible. The bed thing was it was on your way home, and you might be confused / ignored  the signal police gave.

You could go to the court and explain to the judger. If  you had clean driving history, you might get penalty reduced.