Painting Warhammer 40,000 models always tends to put me into a relaxed state, as for gaming, I normally resort to either playing creative sandboxes like Space Engineers where I can construct something either for a purpose or just for decoration or Total War, where I just decide to march entire regiments of men to their doom in darthmod.
Do everything truly critical as fast as you can do it. Get it done. Convince yourself what isn't critical can be done at its own pace. Convince yourself what you reasonably have no control over ought to be accepted gracefully. Once everything truly critical is done, focus on recovery and leisure. If necessary for good function, take time to interject leisure into a routine before the critical things are done, so long as it does not degenerate into procrastination.
Listening to music is good, and reading a good book as have been said by several people already. I sometimes play Minecraft until I feel that the stupid/stress/workday has gone away (not on a griefing server, obviously!). Talking to friends can cheer me up or calm me down. Sometimes ... and it may sound weird ... cleaning or rearranging my room can make me feel better, I think because then I feel I have had a positive effect on something immediately around me. If you have people you can talk to about feeling stressed, then do it! If you have health worries about your stress levels I'd suggest seeing a doctor or health person if you do health people, perhaps a religious leader if you're religious, an older relative if you have one to confide in. They have likely had similar experiences and they may be able to advise you on how they got through it. Lastly you can always call a helpline or find an online help site, never be afraid to do this as they are anonymous and anyway, stress is nothing to be ashamed of. Some people find petting animals makes them less stressed. Like Vulpas says read some funny things online, or watch cat videos if you like cats -something that will take the edge off how stressed you are feeling. Once this is done you will feel a bit more able to cope and then you can look at more involved solutions - I sometimes just tense and then relax all my muscles, starting with my feet, then lower legs, then upper legs etc right up to your facial muscles. You may want to do this lying down. Doesn't sound like much but when it's done even the slightly more relaxed feeling should help you to feel calmer. I hope you feel better soon
stare at cat pictures on imgur (jk) put 80's(or 90's, or 70's, whichever floats your boat m8) metal in the background, get in any shooter with an BFG, grab it, pump up the volume and mercilessly slaughter till kingdom come(or until you get banned ) Hit up a group of friends online to mess around together for the shits and giggles, ARMA, BF, Diablo and the like are ideal for this, Find and play an very old game that has an special meaning for you(fe smth you had played last during your childhood etc.). I have found out that generally warm 2D pixel graphics have an more relaxing effect on me, even if the games were far simpler back then, compared to today, im still getting the same fun playing out of them now, even if its my 12456790. playthrough. Throw an Lan party with C&C95, RA2, CS 1.6, Age of II. (recommended) Another thing i can recommend is playing something in 2p coop gives more haze than simply grouping up, probably due to fact its more personal with only 2 people. Find a game you like and mod it, the accomplishment in creating, turning an idea to reality is whole another and beatiful feeling. If your computer isnt sufficing for something dont give an shit about it, dont be the one that scours the net in the hopes of an holy grail, cause there aint one (well, mostly), just save up until you can upgrade better.
Sweet Mary Jane wants to hear all your problems, and then for you to forget them for a while. Or purge those negative emotions in a cascade of death metal.
Distraction means that you take some distance from the current situation. Keeping yourself distracted all the time from what caused the stress is of course not a really effective method for solving problems. But if you begin to notice that you are trying very hard and that despite all your efforts you cannot come up with a solution, then resting your mind a little bit on more positive and simple matters can help you to move away from a view that you narrowed too much and filled with too much negativity, dismissing too quickly data that might in fact be crucial for fixing the problem.