i feel like shit
You're not sick, but you're just thinking about how bad you've been and how much you've been treated like a piece of trash, and it makes you feel like you're going to die inside.
I was thinking about how I lied to my teacher, and now I feel like I'm going to rot from the inside out.
I spent the whole day thinking about how my brother always steals my snacks, and I feel like a ghost.
I just realized I've been eating cereal for three days straight, and I feel like I'm going to explode.