It happens, and it is not a reflection on you or your organising. Some people say they will come and then get cold feet at the last moment. For survivors especially, the thought of meeting strangers in a new setting can feel daunting, even when they genuinely want to come. It does not mean they will not come next time.
A few things help reduce no-shows: give plenty of notice, send a reminder a few days before, and make the venue easy to reach. If only one other person turns up, that is still a meet up worth having. Some of the most meaningful conversations in SCA UK history have been between just two people in a pub.
If you do not want to go ahead with just one or two people, it is fine to reschedule rather than cancel outright. And if you feel disheartened, post in our community — others who have organised events will understand and can offer encouragement.