I know how you feel man, have 4 presentations next week because I postponed them all. Not for my graduation though. Anyway, being terrified all week wont help, I know that you cannot just shut that off. For me it helps to be really good prepared for the presentation so you don't need to focus a lot on what to say, and accept that youre going to stutter. Maybe talk about it in real life with some people that you're nervous about your stutter for the presentation. And as cliché as it sounds, you make it way more worse in your head than it is in reality. And you have to do it anyway, so I would try to accept that and try to give the best presentation you can give. Wish you all the luck man