I am sorry to hear that you're feeling so sad and lonely.
Seek out whatever slim hope that you have in life
and reach out for help. The hope is precious! IMO, hope is the greatest emotion ~ the most necessary emotion ~ to have in life. Please do reach out to work with a therapist. No reason to put yourself down for feeling this way. (I know, it doesn't matter what I think) One doesn't require valid psychological causes to seek help working through depression.
Science has proven that
depression is a medical illness. The brain is not getting feel-good neurotransmitters. Anti-depressants fight the illness by providing the brain with more good neurotransmitters. It takes a little time to get the brain medically balanced...and working with a therapist about managing these dark thoughts and emotions help you get through the day. Through the hour. etc.
That is worth working towards. Because there are positive parts of life that we all can enjoy.
Gentle hugs to you ~ You aren't alone.