Why does my dog follow me into the bathroom?
Your dog obviously doesn’t care where you go, as long as he can be with you. This means that he trusts and adores you. And dogs don’t care that you’re doing your private business in their presence. Since they are pack animals by nature, dogs don’t like to be alone. This could be another reason why your dog wants to be with you all the time. Or he is simply curious to see what you’re about to do in the bathroom without him. If your dog is protective of you, he might want to protect you in there.
If your dog suffers from separation issues, you need to consult an accredited behaviourist to find the right solution for both you and your dog.