When I was younger, the earliest I can remember this actually bothering me was one day when my mother and I were napping together on a couch. The sounds of her breathing/snoring infuriated me to the point where I had to go to my room and cry. I would always get extremely angry at my brother for eating his food loudly, crunching and slurping. It'd sometimes get to the point where I would freak out on him. His breathing bothered me too. Heavy breathing, eating, drinking, small noises here and there would either infuriate me, cause me to cry, or at the worst case, vomit. The vomiting has only happened a few times of which I can remember.
In high school, once I got an iPod (thanks, mama), I could put in my ear buds through my jacket and not listen to anything in my surroundings. This had a substantial effect to my grades, but it wasn't the only reason I had problems in high school. Because this was my only escape to the torture of everyday sounds that didn't seem to effect anyone else at the time, I usually escaped in music and still do to this day. As a college student, I've explained this thing to certain friends that understand why I'm anxious about certain noises. I've explained to my fiancée that I can't sit with him when he eats, if I am not eating to distract myself. He understands. Even writing this and imagining certain noises as I write them (to describe), I'm noticing my heart pumping more and my stomach churning ever so slightly.
An experience I had recently, today actually, I was in my Intro to Theatre class. I enjoy this class quite thoroughly because the course content is very interesting. Anyway! A person behind me was eating and that made me really, really anxious. I found myself cringing everytime that person would make a crunching noise, whilst eating their chips. I couldn't listen to the lecture going on in front of me. I couldn't take notes. All I could do was listen to each crunching noise behind me and try not to burst out crying. I didn't want to put my earbuds in, because it would've been disrespectful to the professor but HOLY SHIT I COULDN'T DEAL WITH THAT SOUND.
To be specific, the sounds, to me, hurt my ears. They physically HURT me. It feels like knives stabbing my ears. My chest feels tight. I feel a lump in my throat. My stomach churns. Then, I'll either get angry or cry a LOT. I get terribly anxious and I want to run away to hide somewhere. And to think that other people have to deal with this disorder, it makes me feel so awful for those people because it may be worse than the reactions I have.
My apologies for how short this is, but I cannot write anymore about this topic because it's making me sick.
Anyway, if you want to read more about this disorder, WebMD has a very helpful explanation of the disorder: http://www.webmd.com/mental-health/what-is-misophonia