An Accident--Falling down

Three days ago, when I was casually walking down the stairs, I suddenly slid slipped and hit my coccyx on the nosing(???) corner/ledge(?) part of the staircase three days ago. <em>(here the clause of time is too remote from the verb walking that it refers to)</em> It really hurt and my mind was went blank at that moment.
I slowly stood up and felt the pain in my butt while hoping I hadn't broken any bones didn’t broke
My bones are good No broken bones but the bruises and pain will last for several days. How I could be so careless. I blame it on the slippery shoes.<em> (reminds me of the sign in hotel toilets and bathrooms 'dan xin di hua! - it was then translated 'Be careful of landslide')</em>