Please

Please Hi, can you give me some advice because I have to give a presentation tomorrow and I have to present it without any text and I have to know the text by heart. I have the text and I know it, but the problem is that I find it very difficult to relax even when I rehearse it at home. I don't even stutter so much as stumble at the beginning of sentences. Give me some tips on how to relax and manage to perform great. ​