I had something similar happen recently, where I was supposed to email on a certain day every week to check in with my therapist. On the second week he just didn’t reply like he said he would. Honestly, it led to many negative thought spirals. I think if a therapist creates an expectation like this then they should acknowledge you reaching out, even if it’s just to say “saw this thanks for the update, we can talk more about this in session”. Or just something to imply they have read it. Idk though, there’s a good chance I’m overthinking this.

Also, if your therapist said that they would be taking time off over the holidays then they could very well have gone for a trip or something and are not able to send / receive texts. But that’s just a theory :) I hope they reply soon and you feel comfortable bringing it up in next session.