When someone else says/does something you think wrong or hurtful, I don't understand why you don't call them on it? I don't believe other people are as fragile as you seem to think. I can't imagine a "problem" that starts out very large. Of course, I have no tact :-) and just wrote an email to one of my professors because I was trying to help another student and she "didn't get" my recommendations and I appeared to just be making her worse. I didn't want to come out and tell her she was wrong but that's my issue, not hers for not understanding me. I get anxious because I run out of ways to say 1 + 1 = 2, especially when the other person says, "Yes, but. . ." or otherwise disagrees with what, to me, seems obvious :-)

Straight talking is not negative but certainly can be scary to do. If people are crossing your boundaries, you have to tell them to stop. But there's no reason that has to be hurtful. I'm not sure that you quite see how other people feel/are or how they perceive you. If someone "pushes" you, you can be rooted and don't have to apologize or push back. Easygoing doesn't mean being a pushover or conciliatory, especially when your actual thoughts and feelings are called for.

I agree you should probably seek a counselor to talk things over with; I don't think you're "mentally ill" necessarily but could certainly use some help with communicating with others?