I think the part "All the chances that have past me by, would it matter if I gave it one more try?" can be interprented in two ways:
the person is very depressed, and wants to commit suicide. "would it matter if I attemped one more time?"
the person is depressed, and is desperatly trying to get better. The person wonders if it would matter to try to get better one more time, or if he/she would fail.
I think the part "All the chances that have past me by, would it matter if I gave it one more try?" can be interprented in two ways: