It's seriously disturbing

Not in a good mood today. Well, I was, until that happened. After that happened, my mood just went downhill like a rock rolling at um...some degree of velocity, sorry, I hate my physics. Anyway, you know my mentality's kinda shaky, right? Yeah, what happened today just threw me off the ground my sanity is standing on and now I'm hanging by its edges. Coincidentally, it had to happen just a few minutes before my second chance at my add math test. I could barely concentrate due to all those disturbing/irritating thoughts that flew through my head like the ghosts in last year's Xmas carol movie. Then after my test, CY tried to teach me what the teacher taught the whole class today. I got the simple part, but when she proceeded to the more complicated ones, I totally lost her. Everything just bounced off my head at each of her attempt to explain. I also had a chemistry experiment today, I can't properly focus on the teacher's instructions. So I ended up not doing anything significant. Why? The so-called ghosts in my head won't leave me alone!
If you think I didn't at least try to concentrate, you're wrong. I did, again and again, never succeeding. I was bothered all the way home, then throughout the afternoon, and until half an hour ago. Usually a nap would make me feel 'normal' again, but it didn't work this time. I woke up and the thoughts attacked me again. I lay on my bed for half an hour just going through them (expected to find some resolve), which is short really compared to when I'm really haunted with dark thoughts (went on for 2 hours or more before; like insomnia). But overall, I felt horrible for a longer time than usual.
I'm really, really disturbed this time. I didn't expect that small event to affect me so much. Normally, people would just forget about it. But I'm not normal, I have a problem with letting things go. Maybe I should tell her that I can't do what she said because it sets off a 'crazy' trigger in me? Would she believe me? If I cried in front of her telling my reasons, would she think I'm a good actress? Better not, she wouldn't understand anyway. They wouldn't understand. Let alone believe me. I really hope it doesn't happen again, or, I discover some kind of tactic to defend myself first. You might think if I do what she asked, I would be at peace. Wrong, if I could, I would've already done it. I need to have my 'normality' and concentration back, I don't know what I'll do if my mood gets any lower than this point.
Sometimes I wish people could understand what I'm going through so they can shut up and forget I ever existed in their little, tiny, puny, microscopic excuse for a world.

*needed to post this today cuz it calms me in a way. I'm pretty sure you're confused as to what/who I'm referring to in this post.