You are not alone in how you are feeling. Even my mother is depressed and my mother has never been depressed in her entire life (she is 71). She and I are alone and isolated. I have not left my apartment since March 12th and will not be able to leave my apartment until there is a real, effective vaccine against COVID-19. Right now that could be 2022. My mother has to go out and get the groceries and household supplies, but other than that she has to stay home with me as she is my primary caregiver.

I will give you the same advice that has been given me (by doctors, family, and friends).

Work to find something that helps you feel better.
See a doctor if you can and see if you require mental health intervention or treatment.
Recognize that feeling the way you are feeling, given the circumstances, is not unusual (some would say normal).

Read a book, take a free online course (Coursera offers hundreds of free courses), make cards, write letters, come up with a craft you enjoy and do it - even if it is something simple using items you already have.
Find new recipes and cook them to nourish your body.
Start an exercise program that makes you feel better.
Deep clean your living space, one room or even one section of a room, at a time.
Start a gratitude journal and write down five things for which you are grateful every single night, even if all you can write down is that you are grateful that you made it through the day.
Find and watch new programs, comedies preferably, or whatever may interest you.
Create new rituals in your daily life and savor them, make them personally sacred.

Everyone is different so what works for one person is not necessarily going to work for someone else. Everyone is doing the best they can and some people are suffering much more than other people.

There are ways to reach out and communicate with other people if you have no people in your life to talk to - from hotlines to pen pal writing programs to writing letters to the elderly who are also isolated, lonely, and depressed (https://loveforourelders.org/) to volunteering your time if you have nothing else to give (and are able to safely do so).

I wish you the best and hope you make your way through and find something or things that make you feel better.