The first time I left my husband and moved into "the cave" I spiraled into a real bad spot. The cave is a room built into his garage, with one small window covered in thick velvet curtains. When first I moved in here, I played on the computer all night and slept sporadically through the day. I drank heavily. By the time I had lived in this room 3 months, I was in a really bad place.
When I moved out of the cave, I moved into a house with a small above ground pool my dogs and I would sit in for hours. Within a very short time, everything in my head/heart began to be better, and I really believe that it was lack of sunlight that about drove me nuts.
I live in the cave again. I keep the curtains parted so buddy the cave plant can get sunlight. My job forces me to be outside and active, the 2 things that I find are critical to my mental health. It also helps by forcing me to keep a regular sleep schedule and forcing me to have contact with other humans 5 days a week.
My life is far from perfect. Today I am having to work hard to quell fears inside my head that have me all but paralyzed. But I know now to get out and do my 40 minute fast walk, no matter how cruddy I feel, and I know this will pass eventually.