I have similar problems with stairs. It's especially bad if it is a longer set of stairs that go straight without any landings. I feel the need to constantly look down and end up getting a very disoriented, unbalanced feeling. I often feel like I'm going to fall over by the end. I often get this feeling while going downstairs but also have problems going up. Usually I just misjudge my footings. I have fallen several times going upstairs--one time when it was only three steps.

I do exactly the same thing. My muscles will give out on me without any warning and my fatigue level in my muscles becomes almost intolerable. I avoid going up more than just a few stairs with a passion

No one ever understands how scary going down stairs or even stepping off a step ladder can be. Sometimes it's just not worth it.

Yep i take each step sideways and hold the rail like there is no tomorrow, going down scares me but climbing them is my danger time as this is where i fall a lot

I constanly feel like I'm going to fall when coming down stairs and always hold the rail and get both feet on each step before progressing to the next one