Hello i hope things are better for you at thie time. It is okay to cancel the appointmnet but you should reschedule the appointment, and maybe take someone with you and maybe go out to lunch after the appointment. that way your mind is on something positive so the appointment goes better, and you are not as nervous because you are lloking forward to something after that appointment. This way your whole day will hopefully be more positive.. Take care Sincerely Soidhonia