I don't know enough about you or your situation to really say, but I can comment on how things have worked with me to see if that has anything in it.

First of all, according to many and to my therapist too, anger is often considered the least acceptable emotion and people are often taught early to not express it or even have it. That can have very negative consequences since expression of anger is often tied to sense of self. So for me and others too, being able to have access to angry feelings and express them is a good sign, even if messy and uncomfortable and perhaps problematic.

When I have expressed anger toward my therapist, he usually accepts it in an understanding way and most often redirects it to probe the possibility that it is displaced from some other source, which turns out to be the case most of the time.

In psychoanalysis this is very common and considered a way of working through. The whole things is called an "enactment" because you end up in a conflict and possible impasse with the therapist that really stems from some earlier situation that is not yet resolved and isn't completely conscious.

Often expressions of anger and then the assertion of self with them can produce a sense of relief. Still I have never rested there because it has usually turned out that a next step of working through was now available and would produce a more thorough way of dealing with the emotions and issues. And I have found staying with it and going through that has led to a better result and an even stronger relationship as well as less of a tendency for that to happen.