Depression issues??

Okay. So I have a Blue Heeler\ Shari Pei cross. He’s the sweetest dog, but literally goes crazy when he sees me. He won’t stop biting and when another dog gets close, he basically shoves them away. He’s been staying at my boyfriend’s parent’s house while we get finally settled in our place. Every time I leave fr seeing him, he cries and starts to potty all over the house. I don’t know what I can do to break him of this. I’ve tried almost everything I can think of.