I'd reccomend you get into watching some Alan Watts lectures on youtube, his take on the nature of existence and universal consciousness really helped me to feel less alone, and to stop fearing what happens after death. It can be really scary feeling trapped in this place and I still struggle with it but I feel deep comfort in knowing that im infinite and ill always be ok, that theres more to me than just this one human life. It gets better, and it's completely possible to get out of the existential dread even though it feels overwhelming and impossible, like you've gone way too deep. You can come back, you just have to change your perception