I also experience a huge amount of anxiety along with depression. I obsess and try to plan way ahead of time for each possible scenario so that I don't make the wrong decision, so I know exactly what you're talking about. For me, I start by obsessing as I mentioned above, and when I am unable to make a decision I feel paralyzed in my indecision and then I start to feel like every choice will lead to a horrible outcome and there's nothing I can do. That feeling of helplessness is what starts my downwards spiral into depression. I'm not sure if it's the same for you, but sometimes it helps me to breakdown my thoughts; such as what is bothering me, what are possible solutions, etc. I'm sorry you're feeling so anxious. The anxiety in a lot of ways is worse than the depression.