When Im Gone by 3 Doors Down.

I do agree with the suicide idea, but in my eyes, it has more to do with depression in general. Let me explain.

"There's another world inside of me", "secrets in this life that I can't hide"
Both of these seem to be about the actual depression.

There are various parts where light is referenced, or, more so, a lack of. His statement that he might be blind indicates that, yes, he is perhaps suicidal. But he still wants to find the light, and he's hoping that he's just blind.

The chorus seems to be directed at the person closest to him, likely a lover ("hold me"). He acknowledges that he may not be here much longer ("when I'm gone") and that if he does kill himself, it's "only for your good", that's why he'll "give up everything". But he doesn't seem to really want to kill himself, because he asks of whomever the chorus is directed at to "hold me when I'm scared", being when he is considering suicide.

I fully agree that the second verse, primarily "when your education x-ray cannot see under my skin" is about a therapist of some sort. Statistically, most people who are suffering with depression will not say anything to anybody, especially not someone they do not trust.

He repeats "maybe I'm just blind", seemingly as courage to move forward with his life.

This is just what I have interpreted based on my life experiences.