What should I do if my stutter is so bad I can't get any words out?

You could use singing as a stepping stone. Stuttering tends to magically disappear when an individual sings as the maintenance of airflow and voicing during singing allows sounds to come out easily. You could also try stretching and connecting the words you have to say, as it tends to be the initial sounds of words that individuals have difficulty with. In stretching and connecting the sounds, making your words seem like a single word, you can bypass this hurdle.