The reality of life is that we will all die. Some will die quietly, peacefully, surrounded by loved ones. Some will die messily, painfully, alone and afraid. This is the reality we must all live in and accept.
It’s very possible that our species will die out. That is not an inherently bad or evil thing. Countless species have come and gone from Earth. Whether we destroy ourselves through war and ignorance, or we continue to thrive, doesn’t matter right now. What does matter is you.
You describe symptoms of depression and anxiety. You are sad and scared, and this is in part due to feeling powerless to fix the world. However, the only thing you have power over is yourself. Focus on helping yourself before you try to help the world. Try to find peace within yourself before seeking it in the world. The world is not, and has never been, a place of peace.
If you’d like practical advice, then I’d say stay away from weed and THC if it’s making you anxious. Keep away from alcohol as it will just exacerbate your depressed feelings. If you haven’t already, please discuss your feelings with a therapist and see a psychiatrist for mental health diagnoses and treatment. If either of these hasn’t worked for you before, I’d urge you to seek second opinions.
I’m not the one you’re responding to, but I have a recent, relevant, non-biased video here that discusses the issue from a mental health standpoint.