Stress completely shuts me down when I'm under it. I'm left unmotivated and anxious, which usually just makes it worse. Sometimes I'll go into a panic attack under the right circumstances.
Honestly, the best way to deal with stress is is to try to prevent it before it gets out of hand. Like, look at the source of your stress and work on that. For example, one of the biggest sources of stress for me was my difficulty focusing on school back in high school. I was depressed, lacking in motivation, and a procrastinator, which led to me often not getting work done, and in turn, getting poor grades. I never did quite fix this while I was in high school (I mean, I eventually did well enough that I could graduate with my lowest grade being a C), but when I went into college, I knew I needed to change so that I would never have to go through the stress that I do in high school. Since, I get lazy when I'm home, one of the things I do is try to get most of my work done in the school library. I even have a planner to keep track of what I've done/need to do. It's been working out so far, as I haven't missed a single assignment and my grades are sitting at solid A's. It's crazy to think that I'm having an easier time in college atm than in high school.
Of course, is not always easy to fix the source of the stress. Sometimes it comes from things outside of your control (like, perhaps your parents are fighting). However, if the stress is something that comes from you, work on fixing yourself so that you can minimize your chances of stress. Just make sure you don't overwork yourself. One of the things I do when I feel like I have too much work is to break the task at hand into smaller tasks. Say that maybe you have a 1,000 word essay. Maybe write 500 words one day, and the other 500 the next.
For things that are out of my control, one of my favorite ways of relieving stress is to draw. I also enjoy listening to music/watching videos. Sometimes when I do these things, I'll even light a candle. I think candles have a calming effect. I keep one in my room at all times. And talking to a friend about how you feel is always an option.
Comfort foods are also great. Most of my comfort foods are things that are quick and easy to get, like ramen, ice cream, and hot chocolate.
Oh, and naps. Naps are nice.
Just be careful when it comes to taking a break. Sometimes it becomes easy to outright avoid the situation at hand.