Talk to a friend you trust. Studies show there are great health benefits from having a good social network. If you feel friendless, there are several online 12 step programs you can join. 12 step programs are great places where people support each other.
Take one day at a time; just focus on the things that need to be done before bedtime and no more. Keep a scheduler; when you think about things that have to be done in the future, write them down on the day they need to be done and forget it.
If you believe in a higher power have a 'God bucket'. Take a bucket or container, write down your problems and drop them in the bucket. One month later dump out the bucket and you will be amazed how many problems solved themselves.
Engage in some quiet time. Find a quiet place, light some candles and take some deep breaths. Relaxing music will help as well. Close your eyes and scan your body for any areas of tension. Let the tension go and just lie still and breath. It also helps to actually say 'Relax' to yourself.
Cut back on caffeine. Caffeine can make you jittery and make you feel more stressed.
Look at pictures of nature; put flowers and plants in the places where you work or study. Nature is proven to have a calming effect.
Keep a daily schedule. Write down what you need to do for that day and do no more and no less.
Make a conscious effort to engage in deep breathing on a regular basis. You will oxygenate the blood and feel better.
Find a small step you can take to improve your situation. Action is a great confidence builder. The key is to find a very small manageable change that you can take to more you closer to a solution to your problem.
Avoid toxic people who stress you out. You can say No to people who harass you or bother you. Just cut them out of your life as much as you are able.