stress

If the body does not get rest, stress develops. Some recreation such as meditating, yoga, gym, walking in the park, watching a movie or your favorite tv show, playing the game you like the most, listening to music, dancing, gardening, watching the fish in the aquarium(yes watching the fish in aquarium definitely reduces the stress), chatting or other things you like to do the most.

The best way to beat stress is to sleep. Relax and sleep for when you wake up, you may feel better and be able to face the problems well. Analyze and understand the problems then think of things which may help.

Time management and setting-up the priority list. :D Also, do not procastinate. :D