Well, the age thing cannot be ignored.
Are you able to surface it with your therapist? It could result in a very healthy discussion and if not, that is key information in and of itself.
I think it's easy to assume that only older therapist are going to abandon their clients through death or retirement but my T, who is probably about 45 or so, did the same skedaddle routine by leaving my city with no plan on when she would return, and no clear communication about her absence.
Having a T vanish can happen for a lot of different reasons and I think it's worth dealing with the anxiety and its roots and reasons can be a really positive thing that we can do as clients.