Welcome @a.clare71, I’m sure they’re coming from a loving place, but and this is just my opinion … just do what you feel comfortable with. No point forcing yourself setting goals too high then having a setback, although it’s important to build up muscle strength again, of course.
Maybe just draw a up a gentle ‘rota’ of what you’d like to achieve, and if you don’t reach your goal for the day then just start afresh the next day without judging yourself. Gradually build up if you feel up to it.
Could you practice around the house? Again, all this is just my opinion, I’m not a Physio or anything … but you can build muscle strength up again just lying on your bed … your Physio has told you about this I’m sure. Simple leg lifts etc, check with your Physio.
Visualising yourself using your Walker might be helpful, if you’re into that. Relax, close your eyes whilst lying on your bed, in a quiet safe space, and just ‘see/imagine’ yourself walking around at a level you feel comfortable and safe. There’s lots of info online re Visualisation and Mindlefulness.
Anyway, hope this helps, take care of yourself
You’ve made a start and that’s fantastic 
Good luck! 
Anne