I've spent months feeling exactly the same way. Waiting to get into therapy at this point. For whatever reason, I've found that when the "one day at a time" seems pointless because feeling depressed and sad is just an inevitability tomorrow and forever, thinking in terms of "one hour at a time" or even "one minute at a time" (when things are REALLY bad) helps me steady myself a tiny bit. Even if I still feel depressed in the present moment, it takes thinking about the future more and more out of the picture, which reduces the feeling of dread I guess. Have you seen a therapist for this? Hang in there. I hope you find some relief soon.