T.M.
It sounds like his little world has gone tupsy-turvy and this is how he's dealing with it. You have to be stronger. It's hard, but you have to. He's probably feeling insecure and testing you and what he can get away with. I'm sure you've heard that kids always want attention whether it's good or bad and so when he acts up he has 100% of your attention. You need to be the one in control of everything - not him. No matter how loud he screams, cries, whines, you can't give in. Over time (maybe weeks or months) it'll finally start to get better if you stay consistent. Set exact rules about everything, explain them to him so he knows what they are and then follow through with them. If he breaks a rule then he needs a punishment. The punishments that work best in our house is loss of privileges like tv, video games, certain toys, etc. It will be hard, but I promise if you can do this things will eventually get better and it'll give him more security, confidence and he'll be happier. Be strong.
Regarding the potty training, don't worry about that right now. Get the other stuff under control because you can't force a child to be potty trained - it'll happen when he's ready.
Good luck!