Variation in mood and feel like depresse

Off late i feel my mood varies a lot and i get angry for silly reason.. at times i get very depressed.. im not able to concentrate on my office work and get annoyed easily.. unable to enjoy even in outings and keep thinking how to come out of my problems.. dont know how to start or corelate my issues ... till 2004 i was not like this,i enjoyed every bit of my life and was able to laugh and sleep properly.. After getting married to the WRONG person where i was trapped again and again and unable to come out of this trap.. Want to put an end to my life to come out of all this trouble, but seeing back on how my kids, parents and brother will handle this situation stops me from this critical step. i feel i need some professional help to deal with this situation and mental trauma that i am undergoing.