My Little Puppy Is Growling, Please Help?

I just got a 6-month old papillon. It was timid at first but now it is hyper and its ears go up and he growls at me. I am afraid he will bite me or something. He does this a lot when he is hungry, it seems, and also when he has to potty. Any training ideas/techniques to deal with this? I know he is little but still, starting to really scare me