HELP my puppys bad behaviour?

I got a new puppy on monday its a german shepherd cross french mastiff.he's 8week old. He was quiet at first and is now settling down he is always ragging my trousers when I walk so I point at him n with a firm tone I say no bad dog and he growls and barks and shows his teeth then goes to bite my finger!and when I get down to his level he jumps forward and tries to go for my face. Is this normal? Am worried that he's starting to get agressive. I have a dog cage in my house and when ever he does wrong I say no bad dog then pick him up and I say bed then I put him in and lock the door tilll he calms down