Sorry to hear you're not coping with isolation well. Do you not go out at all or see anyone?
I guess having my dog for company is enough for me, I couldn't deal with people living with me, though I enjoy seeing close family for a couple of hours every month.
I do noticed I feel more 'cooped up' if we've had heavy snow and I couldn't get the dog out on the scooter for a couple of days..though I do go in the garden to throw snowballs for him! ..but we're both desperate to get out on our walk by the time the snow clears!!
Is it safe to go for a walk or run once a day in nature where you are?