Disheartened, Distressed and Dep*******!!??

Its a familiar feeling..it takes months to come out of it, and a few shocks later, m back into that sinking feeling again. There were two things that i had tried hard for last year - almost to the end of desperation - an onsite trip and higher studies. Both eluded me till i had to give up on these dreams and pursue something else. Life has been happier after that but today my friends and my juniors (whom i had trained) are going on site. I wonder what makes me less than them that i never seem to qualify. Its not that i desire it, but it does throw me into self doubt. Haven't had good work in office for quite some  time now, almost one and half months, and i have begun to hate office already. Also the feeling of running away and not going home is creeping in. It happens mostly when i am due to go home and its happening again. May b the phobia of answering my parents failed dreams of me, my phobia from self evaluation are pulling me back. But life's like that - a few good moments and a lot of sad ones. I have seen my dad slog it out for every small happiness and now its my turn. I pray that God will lead from moments of darkness into lightness.