Hello!
Personally, breakups like, really suck. I have been depressed since the age of three years old and I am know 14 years old, so 11 years of just sadness and depression. When I am sad I usually cry and when I do it hurts, it is like someone is tugging of my veins and nerves. Breakups can be hard and tough on certain people. What I found what works best, is to talk to people that can understand where you are coming from. Family has been hard on me to talk to because they don't always understand. So try to lean more towards friends that you have known for a long time. Also the answer to your question is yes It can kill you.
I hope it helps!