I am sorry you are feeling this way.
I know exactly how you are feeling. My therapist left for a summer long vacation in June and won't be back before September. I was feeling like suffocating first weeks although she promised she would be in touch with me through emails and she is.
But writing letters isn't the same as in person therapy.
I know you are scared but I also hope your therapist would get back sooner from their vacation. If you had some more session left try to discuss how to go through that period without therapy, I hope you would get some useful advice.
The anxiety will be less and less how the time goes by, I think the toughest is that period before they really leave, it was for me at least and the first week after mine left.
Try to get more interactions here at the forum to get the support you need.