Moody 14 month old!!!

My 14 month old does NOT want to be put down anymore. He used to play independently but now I can't even walk away from him. & oh the temper tantrums. When he throws a fit, I have tried putting him in his crib until he calms down. it worked the first time but my mom and mother in law say that he is too young to be disciplined. I don't think I am disciplining him, I feel that I am teaching him boundaries!! Help mommas, I need advice!! When he gets mad, he will head butt you, smack you, or just throw himself on the floor and try to hit his head!! I'm lost!