I tend to worry a lot about medical things so I'm always unsure if I'm overreacting.
I fainted once, it was summer but it wasn't super hot since I was in the shade, and I didn't feel hot. I had eaten and drank normal amounts that day. I hadn't stood up recently. I'd done some physical activity, but I don't remember feeling tired or worn out at all, and it was nothing I hadn't done before without feeling fine.
So I'm unsure of possible causes. I never felt dizzy or lightheaded throughout the whole thing that I remember.
I was walking and I started getting pain in my thigh. I'd had the same sort of pain before, the only description I have is how I imagine it would feel if all your veins or nerves exploded.
Usually when I had it I'd need to stop walking and my vision would go black for a couple seconds and then I'd feel fine, just a little disoriented for a minute or so. It only ever happened in one leg, never both legs at once, but it switched what leg it was in.
Once my leg started hurting, I had to stop walking and told the person I was with that my leg hurt. She asked if I wanted to sit down, and I didn't because it would hurt too much to move. I remember feeling scared about it like really bad anxiety, but I kept trying to talk normally. I was having trouble understanding what she was saying and I think we sort of repeated the conversation a couple times. That's how I remember it, but my memory seems to be wrong about some things during it.
Throughout this, my vision was getting dark, not black or spotty it just looked like it was turning into evening sort of. Then I couldn't see and everything was black. I remember telling her I couldn't see, but she later told me I didn't say anything. She asked if I wanted to sit down, and I tried to say yes, but I couldn't tell if my mouth was moving or if I made any sound. She told me later I didn't. I tried to reach towards her, but I didn't feel like I could move my arm. I later found out that I did move my arm, I reached out and grabbed onto her and slowly started leaning into her, but didn't fall suddenly. She laid me on the ground, and my eyes were partially open but rolled back, and she went to get someone. I was completely unconscious from the time I reached towards her as far as I know.
I became conscious less than 30 seconds later, but I don't know the exact time. I could hear first, but I couldn't move or see. Then I could see again, but I didn't open my eyes, my vision just came back. I was still in a curled up position, and I wasn't sure where I was at first. My first conclusion was that I died but I was too out of it to care. I was still unable to move. Then I realized I was in my yard and thought I'd have to go to the hospital and was mildly annoyed. Then I remembered I'd been holding a pretty leaf I found and got very worried that I might have dropped it. I could move by then and checked, it was still in my hand which had clenched around it.
I went inside and was exhausted for the rest of the day and had to lay down all day.
This might have some unnecessary detail, but I don't know what could seem unrelated but still be important so I included everything. It hasn't happened since then, but I've gotten similar feelings, and I'm wondering what the reason could be and if this is normal. If age is relevant, I'm a teenager.