Prostate problems

Received a few days ago ,psa 12 apparently , Sharon ( urology nurse ) not concerned as letter says my psa does fluctuate a fair bit , she believes it’s water infection , now got another psa nov & mri , not sure how that will work as also got pre - op ( different issue Oct ) , depends when op is , think they’ve took on my concerns it was getting longer & longer between psa / mri
I must admit I’m a lot better than 3 years ago though that could be were managing to control diabetis better , & no blood / pain , but still think a psa ( simple blood test ) every six months , or do a 2 nd a month after high psa