Reaction to Subpar Days

If I let myself, I could be annoyed constantly for the rest of my life. Before my junior year of high school, I can't remember getting that bent out of shape about things (except for the fact that I was still home schooled). Things are different now, and I have to work really hard not to let people and situations bother me. But there's one that I can't let go.

1) When people insist there's something I'm not saying.
2) When people insist that I'm upset or unhappy with them or a situation.

With the first. Shortly, it's not always a good thing to always say what's on your mind. But apparently I often wear some sort of look that screams, "There's something I want to say." And being told that over and over and over is frustrating. If I have something to say, I'll say it if I deem it appropriate. Let me decide. And if I insist back that "I really don't have anything on my mind," please believe me.

Second. I have good days and bad days. I'm upfront when things aren't going right. Usually I'll at least give a general reason why. Often on bad days, I'm not sociable. I'm not going to want to hang out. I'm going to want to sleep, clean, read, mellow—by myself. This may translate as curt, upset, distant. But this is how my off days go.

If I haven't taken time to explain these things to important people in my life, I should. I think I probably have already, though. And having done that, it's annoying to keep revisiting this explanation.