There's a natural ebb and flow to everything - periods of productivity and fallow times when things are germinating even though you can't express it at the time. If you can find a gig or session (even an open mike night or something like that) that will force you to practice by giving you a goal to work for that might be good. I make short lists (6 to 8 songs or so) of songs I want to learn. Somehow writing down a goal, even if it's flexible, gives me an incentive to pull out the guitar even when I don't really feel like it. Once I've warmed up I start enjoying the practice. If you're depressed - well I went through a little depression myself and I find that singing sad songs to myself - especially the real "tear in my beer" songs - somehow helps. There's something to the expression "Misery loves company". It makes me realize that my little personal problems are really no worse or different than other peoples, that they're nothing new, that they're basically just an integral part of the human condition and I start thinking "Oh well, this too will pass!"