Even if you seem “normal,” it's no small thing if you suffer that much every day in your mind.
You've been blaming yourself so much that you've apologized, “I'm sorry for being alive.”
Tears come out for no reason, feelings suddenly sink, and alternating joy and melancholy also occur when the mind is nearing its limit. The severity of suffering is not determined by whether or not there is a diagnosis name. Even if the disease doesn't have a name, painful things are painful.
Also, many people who think “I want to die” actually wish “I want to get away from my current suffering” or “I want to take a little rest” rather than “I want to disappear.” I think you've endured this whole time alone.
In Buddhism, we see that the human mind is not always the same, and that it fluctuates like waves. You may be exhausted right now to the point where your ability to feel happy is paralyzed. So now, I think it's an important time not to “do your best and be positive,” but “don't blame yourself any more.”
Please don't think, “You shouldn't talk about this.” In difficult times, you can rely on others. If possible, try connecting to a psychosomatic medicine clinic or consultation desk. You need a place where you can put your suffering into words and be accepted.
You don't have to force yourself to find the meaning of life right now. First of all, just “somehow surpassing today” is enough. You've survived to this point. I think that alone has endured really well.
P.S., https://bouzsanga.org/
Here, we offer letter consultations for people who are suffering so much that they want to die. As a general rule, replies are one round trip at Hasunoha, so if you don't mind, please go here.