In this situation, do you have priority over the vehicle driving from the left into the traffic lane?

Why?

You are joining traffic from the petrol station, so you must give way to vehicles already on the road. The car on your left is moving into the lane you intend to enter, but its lane change does not give you priority when leaving the station.

art. 17 ust. 1 pkt 1 i ust. 2 Prawa o ruchu drogowym