depression
"When I was about 15, I started getting these feelings of what I can only explain as "An Impending Doom." I wasn't sad, but whenever I tried to do something that I thought was fun, my whole brain started to freak out and all I wanted to do was shut down. There was nothing I could do about it.

Apparently, this sort of thing happened to most of the people in my family and on my mothers side. So, I talked to my doctor and he said it sounded like a chemical imbalance, seeing as I wasn't sad about anything and I was healthy, so he asked me to try Amitriptyline. Once I started it, all of my symptoms basically vanished and after 2 years I've fully adjusted to it's affects on my body."