I've had depression bouts for decades but it is very occasional now.
One of the big warning signs that I'm heading for a crash is that visually things change. I also feel very flat and my limbs heavy. By visually I mean I will be out for a walk and see e.g. a black carrier bag or an old tyre. When I see these things my brain automatically leaps to the worst interpretation - that the bag is a dead cat, the old tyre is a coiled snake. As I get closer to the object it resolves into what it actually is. I'm also extremely jumpy. Getting out for exercise when I'm depressed becomes impossible due to this - teary, jumpy, heavy feeling, momentarily seeing things.
Does anyone know if there is a name for this thing of seeing things wrongly? I don't think it's derealization but don't know if there is some other name it falls under so I can find out more about it.