I understand what you mean. To be honest, I have memorized Hamlet's "to be or not to be" monologue because this has been on my mind quite a lot throughout my life. While I can sympathize, I suppose there is no answer I can provide. I often like to think what is beyond, if anything, and remain wholly ignorant on the subject.
I'm not going to tell you the world is amazing and that life is a gift because I can't lie nor do I have the answers. What I would like to share is what has helped me tolerate existence as another person with suicidal feeings. The world may not be great and there is a lot of pain, but maybe I can be a part of making it tolerable for someone else or somewhat of a better place. It gives me a goal and a sense of purpose to strive for, so all that pain that I've felt and experienced (and will likely never escape) won't have to be felt by someone else. Just small things that I can add to this world that can make a more positive outcome. Little things like seeing the smile in my puppy's eyes when I play with him, trying to be there for a friend in need, give a little something to charity, etc. Little things are simply that, a little step forward. You may not be able to make life amazing, but you can help be a part of making it a better place. And think about the fact that it was the result of you doing something. Without you here, those small things wouldn't be happening. No one would play with that lonely puppy, less people would give to that charity, you're friend may have been alone without someone to support them, etc. Your existence can be a productive and meaningful part of this world. Even if on a small scale, isn't it worth staying around for them? I'm sorry if that doesn't help, but whenever I want to just end it or numb myself with drugs so I no longer have to feel, I think I about these sorts of things and they help. I hope maybe they can for you as well.
And when it all seems bad, there are little things worth appreciating. The things that make you smile, the things that make you laugh, the things that make you blush, the things that make you think, the things that inspire you, the things that entertain you, the things you make, etc. They can't make life amazing or anything, but they maybe it will all help you cope.
Again, I am very sorry if this doesn't help. All I can do is relate with the feelings and share what helps me cope on a personal level. I know the world isn't an amazing place and it sucks to be at a depressed level to doubt your life will ever be really happy. However, trying to find a compromise and level of meaning despite the doubt and hopelessness may help existence be more pleasant and tolerable than it was before. In any case, I'm sorry you feel these things and really hope you find some solution that makes things better for you. There are no universal answers to these things and wish there was becauuse I would share it with you in this instant so you no longer have to feel this way. Hang in there.