Normal?

I've always only had 3day periods, however its irregular, comes when ever she wants to always just once a month,,since being active on this app I've seen women post awful long stories about there periods,clots, just describing pure horror!I would be terrified if I went to use the toilet and seen a blood clot the size of a worm, I don't even get clots! I've been to the doctor she said I'm fine,,is this actually normal?? I haven't ran into anyone on here with a similar cycle, I'm starting to think my body isn't cleansing itself properly