Re: advice please
this is a good question. They all say one thing: if you in pain, your body tells you something. You will know when it's a good time for you to push, when it's a good time for you to do what you need.
But since you experiencing pain, take it easy. Stop walking after you feel uncomfortable.
If your sciatica bothers you, it means full healing is on a way, but not done yet. Even though your surgery wasn't a fusion, any spinal surgery takes very long time to heal. All of us different, no one answer to all. Some people report they walk 2 miles 4 weeks after fusion, I couldn't walk at all. So you just have to listen to your body and enjoy what you can do, not worrying what you can't do yet.
Best wishes on your recovery.