I'm slightly surprised anyone was working on bank holiday, are you in England, or some other part of the UK?
I was a 4+5 so 4+4 is a bit better. The bone and CT scan being clear is very good. As a general rule if someone has a PSA of less than 30 I assume it is prostate contained, and if it is above 100 I assume it has spread. But this cancer is very variable: we have had people with a PSA of 80 without any cancer at all, and people with a PSA of 3 which had already spread.
So a PSA of 364 I would assume was bad, however blood in semen and urine prior to biopsy is unusual and this could mean the cancer is so disrupted in your prostate that the PSA it produces is getting mixed with the blood and hence you have a very high PSA in your blood, but the cancer may not have spread beyond the prostate, in which case you are curable.
With your PSA of 364 the medics would have been expecting the bone scan to have been glowing with cancer everywhere. I bet they have been checking your patient ID and date of birth to see if they have mixed results up. That they have requested a PET scan is almost certainly because the results so far seem unbelievable.
If you had came on this forum with a PSA below 50 and no evidence of spread I would have gave you a 98% chance of being here in five years. With your PSA of 364 and if there was clear evidence of spread I would have gave you a 30% chance of being here in 5 years. At the moment with uncertainty of spread, I'd give you a 70% chance of being here in five years. If the pet scan is clear I would up that to 90% and if it isn't clear I would drop it down to 50%.
I know figures and percentages like this are just averages and we are all different. Reading tea leaves would probably be just as useful as these figures, but you can be pretty certain your going to live more than a few months, even if things were really bad you would almost still certainly be here in two years. Things don't look very very bad, and they may start looking better soon, if you really want to be miserable and think of a life expectancy I'd be looking at ten years. Until I found evidence to move that one way or the other.
If you take up a dangerous sport like skydiving, mountaineering or even motorcycling you might be able stack the odds of not dying of prostate cancer even more in your favour.