I've attempted like you twice.
The first one was a lot like yours. I grabbed onto a kitchen knife had held it to my throat for an hour, just staring at my own reflection in the bathroom. It took me that entire hour to put down the knife; whether because I was too scared to die or because I didn't want to leave my family with a corpse in the bathroom, I'm still not sure. That was the year I first fell into depression from outside stresses... school, family, grades, future, etc. In the end, I put the kitchen knife back and wore a neck handkerchief until the shallow cut healed. No one who knows me in real life other than my doctors know about this. I was eleven.
That was actually the prelude to the worst years in my life. For years, I regretted not having the courage to just push a little deeper because life just got worse and worse and what started with normal depression plunged into clinical and chronic depression. It climaxed when I was fifteen and seriously could not see myself alive by sixteen years old. I took a month to prepare for my own death... wrote out letters to everyone and shopped around by myself in different pharmacies for pills. I organized my things and enjoyed the end of my days... I felt more relaxed than I had in four years knowing I was going to die.
The night I attempted, though... my best friend called me. I had downed twenty pills by then, one by one, when I got the call. Again, hearing her voice, I chickened out and broke down crying to her, asking if she could sleep over at my place despite having summer school the next day. She agreed, and we spent a night watching Serial Experiments Lain before I finally drifted off to sleep... and woke up the next morning and went to school. Again, no one knew of the attempt, not even my best friend, who just thought I had a very bad day or something. I paid for that attempt by having my joints ache viciously at random when I try go to to sleep.
After that, things got a little bit better. I still have clinical depression, but I also have a lot of friends who are here to support me, even not knowing what's wrong with me. I finally went to the doctors about this last December, after ten years of depression, and they started me on various medications, all of which stopped working after the first two months.
So right now I'm muddling my own way through life like every other person. I can't say that it gets any better. The best thing I can say about this life is that it can't get much worse.
But there
are people who understand, and understand very well. I think you're very brave to actually say something about this. I was too ashamed to tell even the doctors for ten years, after all. When the topic of suicide comes up, I just feel nostalgic and wistful now.
Even though it may take a long time... it'll get better. There's still so much in life to look forward to. Sometimes it might feel better to not have to deal with it anymore, ever; but then there's also the possibilities in the future that you have to look forward to. Moving out. Falling in love. Making a life for yourself. Those are such exhilarations. Don't miss out on that.