My kidney function went from a gfr reading of 33 to 38. what does this indicate?

Nothing really: I'm going to assume that you are being followed for moderate kidney failure by a physician who's good at this sort of thing and that you have a diagnosis. The GFR that's routinely obtained from ordinary bloodwork is a very crude estimate in the first place and fluctuates with your hydration, status of your illness, and much else. Find out your actual diagnosis & outlook & stay proactive.