Thoughts after watching presentation

Generally speaking I am an exceptionally nervous person and personally find the form of presentation as most problematic one. The only way to change this, I assume, is to practice more. Nevertheless, in my opinion it is hard to change ones character and suddenly turn into a confident and socially open person even only for the time of presentation (unless a shot of sth stronger would be allowed). Like most of my colleagues from the course, I felt embarrassed while watching my presentation as it is hard to be critical to ourselves.