Darkside,
I completely agree I have been struggling with this in my interactions or rather attempted interactions with my family. I have heard that sentence "you are too sensitive" from them more times than I can count when ever they push my boundaries.
It's gotten easier over time because I have learned to hold my ground when antagonize to provoke and attempt to bypass my boundries. I've developed better coping mechanism with therapy through trial and error. The trouble is there are some very destructive long standing behavioral patterns within our family dynamic to the point where my boundaries are constantly tested. It's very hard dealing with people who are so combative and subversive.
Growing up with an absent father always away working, a mother who struggled with substance abuse, schizophrenia and violent tendencies, well needless to say there are some unresolved issues.
With my physical health issues from a car accident and some subsequent conflict over that things aren't easy to say the least and I am the only one of my siblings who's sought therapy.
My mother has gotten help after a great deal of effort and I've worked through my past with my therapist and through discussions with my mother. She still has issues but I have been able to forgive her now that i understand her and her problems which was no small feat. It took a lot of work and interacting with my siblings is still tense to put it mildly after all we can only change ourselves but the work was more than worth it.
Guess I unloaded a bit there but I wanted to illustrate my own experience with the subject in question and maybe it can be of help.
Sounds like you have had a tough go of it, but that you are finding your way. To me, working through these issues feels a lot like trying to walk through knee deep mud. It's very slow and a real effort to put one foot in front of the other.