"I want to shoot myself" is often used by someone who is willing to commit suicide and has recently noticed how the world is a shit and want to get rid of it.
To let go of your pride and pursue someone you are interested in
Friend: "He hasn't made the firstmove yet, so I'll have to shoot my shot and slide up into them DMs"
You: "Shoot your shot..?"
Friend: "Yeah, you know talk to him first."
You: "Ohhh, Good luck"
The very quintessence of what it means to be sentient in this explosion encompassing all of time and space in which we inhabit; the truest form of approval and adequacy that is able to be conceptualized by the modern humanmind.