Depression sucks the most; there is no getting around that. All you can do is indulge in some creature comforts (that aren't meth) - warm bath/shower, ice cream (it's a medicine) and try to occupy your mind by streaming movies, reading or whatever. I won't push that "get happy" crap people are always pushing on me during a down cycle. You just have to tough it out and don't let it push you into bad decisions.