Hello Everyone,
I haven't posted here in a few years, I donated 13 years ago and my Sister, the recipient, is still doing wonderful.
I had my yearly physical last week and got some concerning news.  My creatinine has creeped up to 1.45 and my fasting glucose is 99mg/dl, and they told me my A1c shows I have prediabetes. 
My Dr.  recommended some lifestyle changes, loose some weight, drink more water,  eat more healthy by limiting unhealthy carbohydrates and sweets, and exercising 30 minutes/5 times a week.
I have gained about 20 pounds since I donated and I do have a terrible sweet tooth and I don't drink enough water, and I don't regularly exercise.
She also gave me a Nephrology referral to talk to a different Dr.
I'm absolutely terrified.  A nurse did call me this morning and told me I am on the tipping point of the numbers and a lifestyle change would likely make a big difference in reversing the prediabetes.
I guess I don't have an actual question, I'm just scared and would like some advice.
Thank you so much. 

Creatine can fluctuate quite a bit day to day, depending on factors like what you eat and how much you exercise. That said, it sounds like you know what to do -- change your diet, stay hydrated, and increase your exercise. One other consideration is to check your creatinine level (and other biometrics) in six months to see if your current experience was just a "blip" or a sign that your kidney health has actually changed.

Here is information on maintaining kidney health after donation, including a spreadsheet to keep track of your kidney health measures over time: https://livingdonorsonline.org/kidney/afterwards/#:~:text=of%20your%20life.-,Lifestyle%20Choices,-%3A%20Staying%20Healthy%20After

I see you also posted on the LDO Facebook group page, so you've gotten additional suggestions and encouragement there. Stay strong! You can do this!  :)