What your link doesn't say Straight Arrow is the most telling sign of suicide is when a person goes from the things you're describing, depressed, withdrawn, reckless, etc to being perfectly happy again, perhaps even very happy. When that happens it usually means they have come to terms with the decision to kill themselves and are now "enjoying" their last few days alive.

literal people are scary, man, literal people scare me
out there trying to rid the world of its poetry while getting it wrong fundamentally down at the church of "look,it sez right here, see!" Ani Difranco