First off your previous review is irrelevant, no buts. I did good last year but I can’t ride on the back of that and say my review this year should be medium instead of poor because last year was good.
You said there were issues on the project, if there was fault you have to prove due diligence that the mistakes make were no your fault by showing you had all measures in place to stop the errors, communication and training was in place and when the error was spotted you reacted to it appropriately and put measures in place to ensure it doesn’t happen again in the future. Or, the problems encountered were unforeseeable and could not have been prevented by ANYBODY.
If you can’t then you have to accept responsibility and instead of sinking go above and beyond to show you have learnt from these mistakes and jobs go mistake free. If you are responsible yet try to appeal it just says to me and your bosses that you don’t learn from mistakes and will probably do them again.
It’s the fight or flight response and 90% of people when given a bad review will quit, those who stay and learn from their mistakes become better employees.
I’ve had 2 disciplinaries myself in the ten years I’ve worked for my employer and at the time I felt like the world was coming at me but I came back and have fantastic reviews, figures and held in high regard by colleagues. No mistakes made nothing learnt.