How did things end up like this?

Im sad all the time. I can't watch tv or listen to music because it just makes me more sad. Even funny shows and uplifting music. Im so tired all the time because the sadness keeps me awake. People think im crazy or looking for attention. The truth is I just want to be a normal happy person. I don't want any attention, I just want to feel happy sometimes. I cry alot and sometimes tears just run down my face in public and it's really embarring. Ive seen doctors and been on lots of meds and nothing works. Am I going to be this way forever? Cause if I am I think it's selfish for people to ask me to continue living.