this happens all the time. newbie traders see a topic here or some place else or feel the price is going down because they see a mini dump and they panic and start selling, and these sales created a chain reaction that pushed the price down.
but you are forgetting the other half of the market. when there is supply there is also demand. you can't just consider one without the other. and this demand is what doesn't let the price go down.
do you even know how many people are waiting, dreaming, praying to their gods to see a price that is $20 lower so they can buy because they missed the rise?