I can totally see where you are coming from but you can't let it get you down. I've found over time, perspective and how we CHOOSE to deal with our problems makes the situation or breaks it.
Before you assume I've not been at the bottom of the barrel on heartache let me assure you, I've had my heart completely ripped out before by my ex-fiance and my ex-best friend. They have been together almost 4 years now, and are married. For awhile, I was totally inconsolable but over time I picked myself up and didn't let it bother me anymore. It's all about perspective (for me), maybe it's best that they got together, granted it wasn't the best way to do it to me, but if he didn't really love me then in the long haul I'm better off.
I'm seriously worried that you would actually pick up the knife and hold it against your body in a thought to harm yourself. I work with troubled young men, offering treatment and counseling. This type of behavior sadly can escalate into dangerous situations. You need to seek another outlet for this frustration and sadness. Turning it onto yourself isn't healthy and if left untreated has the potential to only become worse. If you need help finding a treatment program or are interested please contact me via PM and I'll do my best to set you up with something, anything that will help you out better than depressing thoughts.
My best wishes go to you brony in your time of need, and please remember, things can and do get better if you allow them to.