If the waitress is really worrying you, go back and talk to her. Explain to her that overcoming such fears/problems as the other day is a step on your road to 'owning' your stutter. If I ever have a super bad block and it's getting awkward I will apologise and tell them I have a stutter. That eases any immediate tension. After this, it is easier to communicate as the stress of 'oh fuck I have a stutter fuck she must think I'm an idiot' is gone. Take it one day at a time bro and don't let it run your life. The stutter wins that way.