To add a point of comparison: my T takes off 5-6 weeks (usually 6) every summer and 1-2 weeks (usually 2) around Christmas time + official state holidays. I find that reasonable.

In your case I think there are several distinct and different sides that to my mind should be processed slightly separately.

1) Your feelings about her absences are very normal and they should be welcomed in your therapy session - even the most angry feelings. I think that if my T should start taking many small vacations more frequently that would upset me too because it just disrupts the normal flow of therapy work. I don't think you should keep quiet and deal with the discomfort by yourself.

2) However, even if you bring your anger into the sessions, she still has every right to choose her schedule. She shouldn't defend herself and should accept all your feelings. However, even if she does that it doesn't mean that she has to obey you and start taking less holidays just because you don't like it. It is her life and her practice and she has full right to run it as she likes.

3) At the same time, if her way of working is not suitable for you, you have no obligations to keep seeing her. You have your own needs and if you need someone who doesn't take that much time off then that's what you need. If she can't provide you the service you need that you have every right to stop seeing her and find someone else who is more suited for your needs.

Anyway, I think the best course of action would not be to suppress anything but talk about everything openly and honestly. Mostly because you need to figure out whether she can offer you what you need or not.