I have days like that too. I had one of those days today. Sometimes you just need to cry it out. It also helps to have some calming activities that you can do, like coloring, drawing, knitting, origami, etc. If you don't have a pet you could adopt one. There are rescues for small animals like rats and reptiles, if you can't have a dog or cat. Listening to music can help as well, either cathartic music that goes with how you feel or hopeful music to lift your spirits, or any combination of the two. You could also make up new things to be excited for, like "Today I will watch this YouTube video while eating a cookie," or "This week I will perfect my blanket fort."