Please? can anyone help? I'm really worried.

I'm 15, almost 16. Since recently I've been having bright red blood come out with my poop. This doesn't always happen, only seems to happen when the poop is large and it does stop after a while. The blood is not mixed with the poop either. I experience no pain while pooping and its just like a regular poop except my anus feels a little sore afterw... more