crutches after fusion?

Hello,

I'm 20 years old and in January I had a spinal fusion at L5 S1. My ureter was damaged in the surgery, which brought me back to the hospital 2 weeks later, in terrible pain becuase my kidneys were going septic, so I needed more surgery to fix that. This delayed my rehabing and 9 months later even with daily physical therapy I still have pain that limits my lifestyle. Yesterday I broke my 4th toe on my left foot. At the er they told me they want me to use crutches, I have tried and it is really hurting my back. The er nurse said I would be fine and that my surgery was "9 months ago and I am completley healed by now" ... I wish that were the case. Sadly the only thing that really helps my back is excersise, and now I can't walk on the treadmill like I normally do. Does anybody have any advice on how to handle this setback? I'm really starting to get depressed about my limitations.