I Was Walking Uphill Caring Some Gardening Stuff In My

I was walking uphill caring some gardening stuff in my arms, I thought I slipped on some loose stones, but I don't remember falling. I don't remember trying to brace myself as I fell. I fell on a concrete sidewalk, my knees hit first (don't remember hitting the concrete walk) but first thing I remember as my face got to the door jam threshold I was concerned that my nose would get scraped. That is all that I remember. Did I pass out? Is this something I should be concerned about? This happened about 7months ago. No problems since.