Why are you unhappy, is it that you are not in a relationship, problems if in school (College), not happy at a job or no job. There is something in your life that only you know that is causing you to feel sad, depressed and down. Also, suicide is never the answer. Suicide is when a person does not have the proper coping skills needed to handle situations that in reality are temporary and they too shall pass with time. A person that attempts suicide makes their life worse both in life an death. You can not run away from life's problems and there are always ways out of any situation, if you would only step back and reflect on putting yourself first and what is best for you. You need to surround yourself with a positive home, school, work and friendship relationships and just live one day at a time in harmony with life and yourself. I hope that all made sense. Life is a journey of experiences...that is how we grow and mature through the best that life gives us and also the worse.
Also, your are 19 yrs old...although I'm not big on pushing medication on anyone, but we women ever month have our periods and that causes great hormone imbalance, which causes, all types of mood swings...make a call to a doctor or your doctor and tell him/her about your mood swings, he/she will be the best person to help you balance your physical state of depression....good luck
Did you go through any loss recently?