Hi,That seedling looks absolutely fine and normal to me, though I wouldn't have a fan on it just yet as it's too small. You would be better off pointing the fan at the light and maybe raising it slightly as that sounds quite close for a HID lamp at this stage, the seedling won't need much light and a 250w HPS will be more than plenty for that little seedling.
You should find the stem will stop stretching as much now as they do this from seed, as I said it looks perfectly normal so don't panic. Stop blowing it over and it will be fine!!
Good luck with your grow, what strain is it you're growing?
I did replant it, attached pictures to a previous post. It is OG Kush from Royal Seeds.