Great thread.
For some of us, establishing the boundary with others that we are allowed to have and to express negative emotions is a realllllly tough one.
In my case, I grew up around an NPD, bipolar, borderline mom.... Which was like being that dumb teenager who just drank some beer and had sex in the horror movie... You knew that the killer was about to mangle them but not which direction it would come from or what the instrument of his/ her demise might be but even with the sound off you know theistic changes and its gonna be bad.
...and so we learn to blend into our surroundings, we learn to be what others need us to be and we learn not to go nose to hockey mask with the bad guy.
I recall vividly when that changed in me and that repressed anger is not sufficiently described by a single word like resentment. Pissed off? Fed up? Mad at yourself for accepting the unacceptable and yielding to someone else's version of what you ought to feel, for how long and howicj and how you may or may not express it?
Them are some big emotions my friend. You can feel what you damned well feel for as long as you damned well feel like it until you feel something different and then you may or may not choose to tell anyone because damnit, they are your feelings and don't require anyone's permission :-)
Hang in there and find some good outlets :-)