is state of mood. you may be in the stage. solution is in your hand. first of all try to identify the cause(it may be environment, people, situations, economic status). if it is avoidable, try to do it, otherwise face it by trying the solutions.
consult your clinical psychologist
for counseling and guidance.
suggestion: do relaxation exercise(breathing exercise
sort out the situation which make you depressed.
write those thing in diary.
take one situation, write the solution for that at least 2. if possible apply the solution, otherwise read the same after a week, you will see the change.
at time of depressed: just desensitize your thought by dreaming your past beautiful experience. it may your happiest moment or place.