Tacrolimus zigzagging and creatinine gradual increase: any feedback?

Hello All,
I had my transplant a bit over 7 months. I had the anti-rejection meds adjusted several times and my WBC finally is back to normal. But Tacrulimus has and still zigzagging from 6 to above 9. Y level should be 6-8. High tacrulimus level is toxic. My creatinine level has been good so far between the normal range but gradually in last few month started to get closer to the upper limit 1.0 and kept increasing to 1.1 and two days ago to 1.2. I had my new kidney biopsy at the 4 month after surgery at Mayo Clinic (my surgery hospital) and tje pathology report and the Mayo team nephrologist assured that there is no sign of early rejection. That was 3 months ago. I sent a message on portal expressing my concern about the trend of creatinine increasing, I am really concerned if this could be a sign for a serious issue. My current TAC (tacrulimus) dose is 3 at 8am and 2at 8pm. Nothing else was warning in blood test except the creatinine level.
I am sure it means something, kidney stress from TAC fluctuations or dehydration which I don’t think so as I pay attention and following how much to drink around 1.5 litters Dailey.

I read some members here they drink water before thy go for blood test , doesn’t this hide the true level? Just asking.
Thach’s for reading my message.
@futureckd