I was almost sure too but i poured hot water on it to kill it (and kill any from my pipes), and the belly part is white (see pic) and i cant find any leech type with white "belly".
Leeches have distinctive mouths, so there's one way to find out. Well, two ways, I guess. You can put it on your leg and see if it starts sucking your blood. I'd advise just checking its mouth parts.