I have been there but may be not to your extent. But here are some steps which might help.
Pick up some kind of physical activity. It can be walking, swimming, playing sports at Cult Fit etc. At least start walking while listening to podcast or music.
Second, pick up new areas to spike your curiosity. It can be a new hobby. Like photography, or world war history, or understanding how brands think of consumers, or dive deep into any sports as a fan. This will channelise your brain to look forward to something and not eat you up with depressing work related thoughts.
Then, look for a new job. See what is it that you are not enjoying in your current role and try to find some thing which doesn't have the same negative aspects.
Wish you good luck 🤞