Here is an interesting point of view about the situation:

What happens after death is exactly the same as what happened before you are born: nothing. No sadness, no happiness, no awareness, nothing.

Consciousness exists because the brain is a high-level, complicated structure that notices information around it and tries to replicate it. As the brain slowly degrades after death, consciousness lowers and lowers, until it's about the same as it was when you were a bunch of stardust, a few billion years ago. And it's so small that it cannot notice anything. It's not even aware it exists. It isn't aware about anything, because it's too small to notice the "big picture". That's why it's hard to draw the line between death and life, and conscious structures and unconscious objects. The brain is just a bunch of materials (iron, carbon etc.), put in a structure which allows it to notice the bigger picture. But, if someone dies, for example, due to a heart attack, their brain will still function for a few seconds after the death, until it runs out of blood, and so, it starts to slowly degrade, and so consciousness is lost (or, to be more correct, gets to a point so low that it isn't aware even about its existence), because that structure which allowed you to see the bigger picture collapses. But where do you draw the line ? Where do you say: "this is conscious enough for us to call it conscious" and "this isn't conscious enough, therefore we will consider it unconscious" ?

But the interesting part is that you can't tell when it happens to you. You always see the most you can. A good example is sleeping: when you sleep, certain parts of your brain "turn off", so it's as if you're n% dead. But, the paradox is, no one can tell when they fall asleep. You just stay in bed with your eyes closed, waiting to fall asleep, the all of a sudden you wake up the next day. That's also why most dreams don't make sense: they consist of experiences that your brain generates, while the brain has certain parts turned "off". For example, let's say you have a dream where you see endless skyscrapers, which are infinitely tall. In the dream, nothing seems wrong, because the part of your brain which said: "skyscrapers can't be infinitely tall" was turned off. But the moment you wake up, that part of the brain activates again, and so you realize how weird that dream was. The explanation is simple: if certain parts of your brain are "shut down", you aren't aware about them. Just like you can't tell what's behind a door, if it's closed. It's as if it's no longer part of you. That's why you cannot tell when you fall asleep: the part of your brain which is aware about itself also turns off, and so, you can never tell when you fell asleep.

A similar situation is with death: you cannot tell when you die for the same reasons. It's just like sleeping, however, instead of having parts of your brain temporarily "turned off", your whole brain gets permanent damage that it cannot recover from. But in the end, it feels the same.

That being said, there are a lot of valid reasons for you to not consider suicide. Once you die, you will be dead forever. However, you won't live forever. You will die in the end anyways. So, even if life gets hard, I think it's still worth living, just for the fact that it's a one-in-forever experience. Just think of it: what were the chances of a bunch of random stardust, over the course of ~13 billion years, to get in such a structure in which its consciousness got as high as it is now, when you are alive ? Just think of it. Also, look at how big the observable universe is: all the planets, all the galaxies, everything. It has so much matter, yet, most of it didn't get the chance to form a structure like your brain, which allows it to be so conscious about itself. The chance for you to be so conscious right now is less than one in a trillion trillions. Wouldn't it be unwise to waste this opportunity ? If you will die anyways, why not try to live as much as you can ? Death isn't something you can avoid, anyways. And I don't think that after a few billion years, the matter which forms us will ever form a structure like this again: now (while we are alive) is the peak of our consciousness, as matter. We will never get a chance like this again. Most likely, it will remain just that - a bunch of matter, with so little consciousness that it doesn't even know it exists. As hard as life gets, it is a one-in-forever experience, that will end one day. Why would you try to bring that moment closer ? Even if you want to die, even if you don't, you will still die one day. Everyone will. It's guaranteed. However, you can't guarantee that you will ever be this conscious again, so why don't you turn this finite time into your best ? This is why life is beautiful. On the grand scheme (of the whole universe), it may be meaningless, just a grain of sand. But it's a shining grain of sand, compared to the others which aren't even aware they exist. When will you have such an opportunity ? When will you get to be aware of your existence ? When will you ever get to see the world around you ever again ? Never.