My sweet friend, you've done the right thing in acknowledging to yourself that you feel like you are sinking. The world wants you to stay here among us. Just because you are unhappy now doesn't mean it'll always be this way.
Please don't feel disappointed in your social support system or yourself. It's likely that one or more of the following are true:
1) While those around you who love and care for you want desperately to make it all better, they don't have the right skills, experience, or insights to do so. Thus, the deeper you fall, the more confused they feel about how to help.
2) They may not understand that the gravity of your issues includes suicide unless you have been absolutely explicit with them about it -- and even then denial may be at play.
3) You may very well have a biochemical imbalance such as clinical depression that could be remedied with medicine if you saw a professional.
If you are in crisis now, immediately contact 911, one of the crisis lines mentioned in this article, or one in your community. We need you here, and we need you feeling well.
If you are not at immediate risk of self-harm, then contact a clinical or counseling psychologist, psychiatrist, or another qualified mental health professional for an appointment. Do this today. You could start with the names your insurance plan permits. You can also ask your family, friends, and family doctor for recommendations. If your income is limited, there are many that provide services on a "sliding fee schedule." A social support system is crucial, but I cannot emphasize enough that you need to get to a professional who can help you.
As far as general strategies for hanging on, here's what I can offer:
1) make a gratitude list of all the things for which you are thankful for, no matter how big or small. Perhaps write a paragraph about each: your friend who does the awkward celebrity impressions, your dog and his sloppy wet kisses, the way your mom sings off key to 5 Seconds of Summer and thinks she's nailing it, being an American, the smell of fresh cut grass, Chick-Fil-A -- whatever is important to you.
This list is more than a distraction. It's an evolving list of the reasons why despite all the shitty things that go on in this world, it's worth having you tough it out and stay here for the long haul.
2) If you find yourself in a bind, feeling like you might harm yourself, STOP. Do what you need to do to delay acting on the deadly impulse. Tell yourself you're going to discuss your decision with three people first to see what they think. (That's what you'd do with any other major life decision, right? You'd talk to people -- probably several of them.) Then, call 911, a crisis line, or your therapist for help. Or decide to wait a day or a week, then another. Postpone it until the feeling passes. This is not a substitute for getting urgent help but rather a way to keep you here until you can get access to the resources you desperately need.
3) Keep trying to share your feelings with your social support system, and let them know the severity of your dark feelings. If you cannot say the words out loud, the write them down. Ask for their help, and be specific. You need them, just as they need you.
4) Build yourself a safety net by removing firearms from your home and avoiding alcohol and drugs which could impair rational thinking.
I reiterate that the world needs you here and feeling well. Please stay here with us.