normal bun with elevated creatinine

Except for my initial lab work which showed a BUN of 24 and a creatinine of 1.5 (high normal 1.2,) my Buns have been running around 14 (7-25 range) and my creatinines have been between 1.44 and 1.56.  I've searched and searched for an explanation in the net and the only possible answers I've found are working out ( doesn't apply to me), eating a lot of meat (not me but I"m not a vegan either-I eat turkey and chicken, yoghurt, cheese) or muscle disease.  I have a bad trigger point and carry a lot of tension in my muscles (I have quite severe anxiety/tension/depression probems, especially lately.  My NP doesn't understand how my BUN can be OK, but have a persistently high creatinine.  A U/S of my kidneys did show "medical kidney disease."  Looking back on my past creatinines,, it's been a slow increase since 1993.  I don't take any of the med.s (as far as I know) that would account for only a creatinine level.  As you can guess, this has contributed to my anxiety level and am going through a clinical depression now. I also recently had an elevated TSH.  Can you think of a connection? Nephrology and endocrinology are so complex.  I'm an RN and have read so much.  Anyway, I so appreciate the availability of this forum and you.  Thank you.