PSA rising after RARP

I was diagnosed with prostate cancer 5.5 years ago, and had a complete removal of the prostate.

I have been having regular PSA blood tests every 6 months which started at 0.01, this rose to 0.02 last year, and my most recent test a week ago, rose to 0.04. This was hopefully going to be my last test as I was at 5 years

I have now had a letter to say that I will need another test in 3 months time. Having googled as much as I can, I’m now frightened that the cancer has come back and spread.

what can I do?

Thanks