You're not alone in this. I feel lucky to still have a job and one that is remote-first, but working alone in my studio apartment is really getting to me. My family is in another state and a lot of my friends don't live in a bike-able distance or have temporarily moved out of SF. My productivity has really been shot into the toilet.
One thing I'd really recommend is making sure that you exercise regularly. There are great apps like Zombies Run or Peloton (there are normal workouts - bike not required) that can give you a great workout. They also have hooks to keep you engaged (storyline, Peloton's community) and help you maintain momentum. Strava has also been a great way to see what my friends are up to in a way that's toxic like Facebook.