I Had Spinal Fusion Surgery In February And Have Experiencing

I had spinal fusion surgery in February and have experiencing numbness in my feet and legs and cannot work the surgeon is now saying this could take up to 18 months before they know if the surgery was successful or not. I came out of surgery 10 tines worse than when I went in. I have my L5 L4 and my s1 fused together and a spacer to lift up my dis. Does this change sound right?