Low Creatinine a Problem?

After being diagnosed with type 2 diabetes I had some issues with microalbumin. That has since been resolved with my blood sugar now under control but my doctor said there was probably some level of kidney damage that I have to monitor. A recent blood test showed a BUN of 12 and a Creatinine of .6 with the GFR >60. All other metabolic tests were within the ranges. I thought those numbers were adequate but he mentioned some concern about the ratio between BUN/Cre and the low level of creatinine. I thought low blood creatinine was a good thing. I'm 42 yo and weigh 145. I try to watch what I eat and exercise and am on BP meds and Metformin. Any insight into these test results is appreciated. Thank you for your time.