I'd like to tell you how even objectively bad circumstances do not demand subjective suffering, that there exist treatments and substances that can genuinely help, to try to point you in the direction of Standard Official Resources, and that the future can be better and so on, but I also know that all of that can sound empty or even annoying.
So instead, I'm going to try something that might be unwise. I've only seen it work once.
You're not alone, in the worst possible sense of the phrase. Extreme suffering is common and nearly ignored. Through what can only be reasonably termed negligence, more people die each year to trivially preventable causes than at the peak of the holocaust. Unanswered prayers and extinguished hopes are the sum of experience for a number of people so large that we can't have a proportional emotional response to it.
You have a blessedly uncommon insight in this. Even if your experience isn't the same as all the others, you have an understanding that reality has no safety net.
So now we come to the part that I've always hesitated suggesting to anyone else:
Please help. Please take upon yourself the completely ridiculous and unreasonable burden of doing what is within your physical power, even when it means exposing yourself to even more suffering indefinitely, even when doing anything is already asking too much. It's not a matter of obligation or moral expectation, there's just the brute fact that people constantly suffer and die for no reason, and they could be saved. Just actions and consequences.
I won't tell you that this will help you. It may. I am alive right now. Therapists might suggest 'crying yourself to sleep for a year' and 'having recurring dreams composed solely of uncontrollable sobbing' are not an ideal recovery from severe depression, but if all else fails, turning yourself into a robot that tries to guide others away from the sharper edges is still better than the alternative.
Please stick around and help, because no one else will replace you.