+1, an incredibly important point. Feeling detached/disconnected from the world is one cause of depression. Feeling disconnected is a logical outcome of changing everything about your life all at once.

Changing habits/attitudes/etc. is important, but I'd try to do it incrementally - testing to see if these changes improve your experience, while focusing on maintaining and strengthening connections to things that you think make life easier/more enjoyable (could be friends/family or work or hobbies or ...)

[I'm not well versed in psychology, please take this as an idea to start your own research, and not a prescription of activity]