Damn pre-meds are already plenty scary, I can only imagine how cutthroat and high-pressure it gets once you get to the big leagues. There's a lot to lose and by this point you've already put in lots of time that you cant get back. Its perfectly reasonable. You're not alone in this, sure you're a pretty special case since you're a doctor and all, but failure feels like failure to everyone.
Is this your first time considering ctb? This intense emotion is normal in dire circumstances, maybe in med school no one wanted to admit it, but depression, shame, failure, and intense anxiety are feelings everyone will experience at some point, even people who lead successful lives. Doctors as a profession have one of the highest rates of suicide, it sounds like the stigma combined with the competitiveness of the field often puts this kind of strain on people.
I agree with everyone else. You have lots of potential, while it may feel like your life is over, it isn't really over. You'll wake up a year from now, and not being placed will not have killed you. Its in your hands. You can always ctb later. There's no rush, if your life still sucks a year or two from now, then you can weigh your options again.
I think you should see a therapist, feeling like you wanna kill yourself is bound to happen to most people but thinking of your exact method and registering on a site like this isn't. You have the financial means to get adequate care, you should ask your parents for their support. I'm sure they will understand why you're so hurt by this. you dont sound like youre severely impaired by mental illness like other some people on here are. You got through medical school and even though you say your relationships can be troubled, it doesnt sound like youre super socially impaired or bizarre. You have a bright outlook, seriously. This is something you could survive.
Just because your parents/med school peers act like you're not living life if you're not a doctor, doesn't mean that's reality. So far you've been living in a very manufactured form of reality where hard work and statistics must cause certain outcomes for everyone. But the world isn't like that, bad and unpredictable things happen sometimes for no reason. Go out there and do something else with your life if you want. There's no path or rules you have to follow. That's all made up. Your choices are your own, and there's lots of opportunities to help people with the knowledge you've gained so far.
You said you were aiming for a psychiatric residency. Idk how med school works, maybe you've already dealt with severely mentally ill people before? What would you tell a patient if they've just flunked out of high school and tells you that they want to swim into the ocean and shoot themselves? I'm sure you would have consideration for them and do your best to treat them. You need to treat yourself with that same thoughtfulness and forgiveness, give yourself that treatment, and think things through. Good luck, I hope you feel better.