I am glad to help you feel hopeful for this guy/gal. You have already done some good things, like not letting it touch the glass.
Yes, I think it is sort of 'plant S A D' .. it's just hard for it to 'get up and go' when days are so short, dim, and cool.
My own coffee spends summer outside in shade, gets blown over a dozen times, because it is leafy and catches the wind, then comes in corner of my bedroom for winter, It isn't even in front of a window, but between an east and a south- maybe the light is a bit better than I give it credit for. And it is a plant I feel uses water faster than some.
My plant also loses some leaves inside for winter.. older ones.. while getting new ones. Picture in a minute..
