External hemorrhoid?

How much blood should come from one. I have dhiarrea all the time since my gall bladder surgery and i have a sedetary lifestyle so i figure it must be hemmeroids. It itches sometimes but just recently i went to the bathroom and blood was on my underwear and i looked i had a good bit of blood in my area now its not pouring out it stopped i took a shower and its not bleeding anymore. im only 20 so......whats up?