The following rules for motorways and motor vehicle roads are stated in the traffic rules:

It is prohibited to reverse or turn around on a motorway and on motor vehicle roads or in motorway and motor vehicle road's acceleration or deceleration lanes.

It is prohibited to stop (or park) on a motorway and on motor vehicle roads or in motorway and motor vehicle road's acceleration or deceleration lanes.

Your only option is therefore to continue onto the motorway.