I think pyjama days are okay now and then. They can be therapeutic even.
If you are feeling sad however and lacking motivation most days then that is different.
I am wondering if there are ways you can get your nature fix in the city? Are there public parks you can get to? What about small scale gardening? Growing something on your window ledge even?
I think many city dwellers share your longing for a greener space. Nature calms, connects and invigorates us.