Your creatinine is within or close to the normal range if you are a man, and perhaps a little high if you are a woman. For reference, dialysis starts when someone's creatinine reaches around 10.0. Also, your GFR is not that low for someone with one kidney.
My husband, who was my recipient, has 1.4 creatinine or so. He feels great, as compared to how he felt right before the transplant.
It seems unlikely that your fatigue is caused by your kidney functioning - you should get a full medical work-up (and consider psychological issues such as depression, anxiety and stress) to see what else might be going on.