Sometimes depression feels like a mental upset stomach. You ate something bad and now your guts are telling you about it big time. But mentally. Like you had a bad experience and now your mind is either refusing to let go, just getting completely mentally constipated, however you try to get these thoughts out of your head it won't work at all, it just hurts and doesn't get better. Or your mind is going a bit nuts, expelling random feelings explosively. There's a steep pressure build up and then you can't hold it in anymore, you explode in rage or sadness and it feels horrible and afterwards you're weak and tired and feel a little bit gross.