Hi Richie,
Score another one in favour of following the doctors advice.
My MRI came back a 4 and that triggered a biopsy, which, although I wouldn't have one as a hobby, wasn't as bad as I thought.
The biopsy came back negative for cancer cells.
The 3 score your MRI gave you means it's not necessary to have the invasive biopsy at this time.
I know how hard it is when you think there is something going wrong inside you, but you have to be realistic and appreciate that sometimes watchful waiting is the best option.
As previously said just keep on top of future tests. My GP has been fantastic and pencilled a reminder in my medical notes to call me in for a psa test at the appropriate time so I don't forget.
Mick