To deal with stress and/or anxiety, you should meditate. Meditation quiets the mind and allows you to truly relax. It's somewhat what of a catch 22, because you have to relax yourself to reach that relaxed state. Many people don't have the patience to meditate, but if you learn how to meditate, and practice it consistently, you will gain more patience in your life.
Please don't smoke weed to deal with stress or anxiety, because you are not attacking the root of the problem, only putting a bandaid on it. When you use drugs or alcohol to deal with stress and anxiety, you create a vicious cycle that can end with addiction. Smoking weed makes everything cool, but only for the time frame in which you are high. After the high wears off, you will want to smoke again, because you didn't address the problem, you only forgot about it for the moment. This is how problems get buried deeper and deeper.
Weed is cool, but if you partake in it, it should be used in moderation. One of the keys to life is balance. If you smoke weed everyday after school, work, or just in general, then it's a problem. I'm sure the weed heads will come in here up in arms, but I am only speaking the truth. I smoke myself, but I don't make a habit of it. I haven't smoked since December of 2014, and I don't know when the next time I smoke will be because I do it organically. I might smoke next month, and I might smoke 2 years from now. The point is, you don't need weed for anything.