Terrible twos early?

My son is 19 months old and has been having bad behavior problems. For the past two months we have been having huge problems with him throwing fits in public and it's so bad that I'm to the point of where I don't ever want to leave the house with him. I try to ignore it and not give him the attention he's wanting from it hoping it would stop but it doesn't. I get so many rude looks but I really just don't know what to do. I've also had problems with him hitting and throwing stuff at people, I've tried time out but it doesn't work for him. I'm just so lost I on what to do he can be the biggest sweetheart when he chooses to be but other times he's extremely mean.