I practice. Presentation is planned, memorized, practiced in my head, then out loud, then in the mirror, then in front of a friend or coworker, then in the space I will give it . Not having to think and knowing my material cold helps me feel better which helps me speak better. Give yourself some levity, it is school so it is a bit like practice for the real world. Easier said then done but have a tiny bit of fun with the process and fuck the rest. Civil engineer, out of school 5 years now. You can do it.