Chances are you probably haven't gotten enough sleep this week. Sleep is essential in keeping your body healthy and happy. You will feel better if you take a quick nap. All you need is about 26 minutes. You can spare that much time, believe me. It will help you be more efficient.
It may seem like you don't have any time to do anything else but study, but in reality you can spare at least 10 minutes. Take a short walk around campus. Exercise reduces stress levels. Once you get back to studying, you will be more relaxed, and your mind will be more alert.
Don't study while you are eating. Take that time to just be you and to think. You will be grateful that you did.
If you listen to classical music while you study, it will reduce stress and help you pay attention more. (As they say in the Incredibles: "Mozart makes babies smarter!" Surely, the same is true of adults!)
I have a little hand-held massager that I use, but if you don't have one, there are many ways to massage out those knots you've accumulated bending over the computer. If you happen to have a tennis ball, take it and lean on it against a wall. Find where on your back that it hurts the most and keep the ball pressed there. Eventually the knot will give up and loosen up. You can also do this using your fingers. Just press until it releases!
I know, this can't possibly be a thing! It is! If you eat a small amount of candy, it actually has a lot of benefits! If you eat peppermint it increases your concentration and chewing gum releases stress! Just pop in a piece of candy. You will be happier and healthier too! Just don't go overboard with it!
Taking deep breaths lowers your heart rate and helps you relax. At one of my acting workshops, I learned this technique: breath in for 10 counts, hold for 10, breath out for 10, and hold for 10. Repeat this until you feel better! It definitely helps!
I have a professor that has to eat a banana before every recital. This isn't just a ritual. Bananas give you energy and help calm you down! They have so many benefits that I would have to write another post to get them all in. Besides, eating a snack while studying is a good break from work. You will be able to recuperate.
A way to feel calmer is by getting your muscles to stop relaxed. The best way to do this is by tightening every muscle one by one from your feet up and letting go. You will feel so much better after this. I usually clench my muscles to the count of ten and then release.
Have you tried any of these? Or any that are not on this list? What works best for you?