It really sounds like you were not properly diagnosed or treated. Metformin can can help mild glucose problems, but it can't correct when your levels go as high as you suggest. It is possible you are a type 1 diabetic. Have you seen an endochronologist? Did you get help with your diet and exercise?
I actually believe that with good blood sugar control, you can heal from some damage. You can heal from minor kidney damage and stop further damage to your eyes. You can work through this. I hope you stick around, let us know how it is going and if we can help you through this that would be great.