am i depressed or just overreacting

[bhaiya1]

3 years back...Due to some reasons i was not able to score good in an exam for which i worked really hard for 2 years.. I have been an A grade student from the start..But after that Failure..I felt and still feel like... m drained of all my enerygy...i used to love studying But now when i open up a book i just cnt muster courage to read it...i have frequent headaches..from past three years ..had a quite unstable personal life too and a lot of betrayals..Now m also having trust issues..Now i cnt seem to figure out that m i suffering from depression or just a mood swing?

[Bubulous]

What has likely happened is something that happens to me sometimes.  You have lost your momentum and I would guess that you must have had some pretty good momentum to feel like this.  This is an unfortunate thing to happen but it often happens to those with un-balanced lives.
It seems like a certain part of you self destructs around the same time every year.  It is likely that you subconsciously are afraid of gaining momentum again and losing it because of what happened to you on the exam and I hope you undesrtand that this is going to be a pattern until you break that cycle.
I would recommend re-inventing yourself in a few ways so that you are not  that person anymore.  If your life someday leads you back to the path you were on once and loved, that's great- but if it doesn't you may find a new path that suits you fine.
Until whatever void it was that started this whole mess is filled you are going to be spending a lot of time searching for an answer that may never come.

[bhaiya1]

computer science and engineering...
my whole lifestyle kind of changed...
earlier i was always full of energy good overall health
now m sleepy the whole time although i get a good amount of sleep at night..
i get frequent impulsive headaches.. 5 times in a week or something..also i have headaches in a particular period of  year that is june july august..its the time period where i had to deal with the failure in the examination and a lot of personal life havocs..betrayals..break up..
earlier i had a hunger ..a keen desire for knowledge for learning anythn new..now i have kind of lost interest in everythn..i feel pretty much lifeless..as if there is no meaning to my life...sometimes it feels like i have forgotten how it is to actually smile. Moreover, It has probably affected my immunity too coz i get sick pretty frequently

[Bubulous]

You say "due to some reasons"
What do you mean by that?
There may be something going on or nothing.  It is hard to tell based on what you have written.
You are at an age when some extreme changes can occur but if you could go back to before that exam and tell a little about the changes in your life that would be a good start.
What are you studing?