Why am I depressed..?

I don't really have a complete answer to that question.. When I was 14 I came across papers that said I was adopted.. & that really messed me up.. My parents weren't fit to raise me.. They were addicted and doing all types of drugs and I was actually born addicted to crack and deaf(not deaf anymore started to hear around 2). I do think my depression is biological since drugs are depressants and I think learning that I was adopted triggered it.. 

     I've moved past the adoption part.. I understand I was blessed because I could be anywhere else right now but I'm in a economically sound family, in a nice house, on a computer, physically and mentally well.. except for the depression lol.. but my life could be so much worse than it is.. I do understand that.. but the depression is still here and that's what I don't understand. I probably  inherited a vulnerability to depression from one of my "parents", that my  brain may have reacted to a stressful event(finding out I'm adopted) in a way that caused me to get depressed. I read that in adopted children I have three times the risk of having depression.. so that might explain a lot. 
    Hopefully soon I'll be on antidepressants and things will go back to the way they were and I can be called a survivor.. But for now I'm just making it one day at a time.
This post deserved a picture...

 Even though the light at the end of the tunnel may not be visible.. it's there, just hold on. We can walk there together.

Depression Is..

Depression is when sleep is so much better than being awake.
Depression is when "just" becomes your least favorite word..
Depression is when you just lay around all day because you are too depressed to do anything
Depression is when you go to school and work and you are unmotivated to do anything..
Depression is when you wish you were lazy because you could actually do something about laziness
Depression is when you have no hope, no perspective, when you are unable to see the future..
Depression is when you feel weak, embarrassed, on the verge on tears if not already crying because you are unable to do what you used to and you have no idea how to fix it.
Depression is those mornings when you ask yourself why am I doing this (life) again..
Depression is when you get irritated over the littlest things so you take your problems out on others.
Depression is when your smile covers everything..
Depression is those moments when you can't even speak because you are so overwhelmed so you just go into the dark room and go back to sleep.
Depression is the relationships that are ruined because you isolate yourself so bad you just can't talk anymore.
Depression is the days when you just throw anything on and head out the door..
Depression is the days you can't eat and the days you eat everything in your sight.
Depression is the hurt that you face when someone says "Just be happy"
Depression is the envy you have when you see people do a lot and you can hardly get out the bed to clean.
Depression is the instigator between yourself and yourself. It makes you the worst enemy of yourself.
Depression is the nights you just want to die. You stare at the pills for so long. You feel like you can't handle life anymore.
Depression hurts but why do we have to?