I've fainted 3 times. The first time was when I was 16; I was in a shop with my mum and sister, I felt a pain in my stomach, got dizzy, my vision darkened and became blurred as I began to fall and I was unconscious by the time I hit the floor. Fortunately the back of my head landed on the toe of my sister's hard leather boot instead of the harder concrete floor. I was only out for a few seconds, but it took a while to recover afterwards.
The other two times happened at home; I have a scar on my septum from when I hit my face on the rim of the toilet bowl the second time, and I landed on my washing basket the third time, so I didn't have any injuries that time. There have been times when I've suffered from frequent dizzy spells where I'll suddenly feel faint, my vision will darken and I'll struggle to keep my balance and remain upright for a few seconds; the dizzy spells would happen several times a week over the course of 3-6 months, and infrequently at other times. They don't happen when I stand up from a sitting or lying position; they tend to occur when I'm already standing, often when I've been walking and come to a stop, but also at other times when I'm physically active.