How to get rid of this impulsive urge to kil* myself

I don't know what kind of mental disorder I have, but there are some very very specific triggers which when triggered cause me to feel extremely suicidal, happening with me just now. I just feel there's literally nothing, I mean nothing for me in this world and I just want to stab/hang/suffocate or throw myself in front of a truck NOW!! This feeling as I've experienced before too will go away within an hour or so, but i fear someday if I actually act according to my extreme thoughts I'll surely die or be injured to a point where it'll be better to die than live. I request to anyone reading, please help, if there's anything that can be done. The trigger is basically any kind of scolding or yelling by one of my parent, and it's nearly impossible for me to confront or talk about it to my parent. They won't understand. But I want to live. Any way to release it? Everything is bottling up!