Recently had an appendectomy, need advice on how to workout (can't strain abs).

Any advice. I had my appendix removed two weeks ago. My doctor advised that I not strain my abdominal area as this may lead to a hernia (because of the surgery).

I used to work out mostly with free weights 3x a week (full body workouts). My doctor said I can use machines, since they tend to isolate muscles groups so less straining.

Any advice or link to effective machine workouts? I always feel I’m not working hard enough when using machines, it feels like “cheating”. I’m pretty much at the intermediate level, however I don’t want to just stop training. Any help would be appreciated.