It sounds like it was the right weight. Snakes don't get hungry the same way we do, and they are not hunters like lions so they don't go looking for more food. Just feed the snake the right sized food, and then feed it again next week. It's that simpe
Edit: Snakes will often eat more than they need, if you offer it 2 rat pups each day for a period they may eat it all, because in the wild (and in their head) it can be months before the next rat shows up!