Okay so possibilities include:-
- you were accidentally given the 1 month injection rather than the 3 month version
- the injection was given or stored incorrectly
- the HT is not working well enough to castrate you
- your cancer has become hormone independent already
- you have a rare type of prostate cancer that is not affected by HT
Any of these would be rare / unusual. In your shoes I would be tempted to ask the nurse to confirm the dose of your last injection (should be on your medical record). I would also confirm that the biopsy had identified adenocarcinoma rather than one of the rare prostate cancer types. Assuming that is all confirmed, I would ask for a testosterone test - if your testosterone is at or below 0.69 then the cancer may have learnt to be hormone independent and if it is above 0.69 the hormone isn't working well enough.