Hi everyone! we adopted a bernese mountain puppy about 8 days ago, from family members who couldn't handle and care for him anymore (they have 2 little children). He seemed fine at first he loved me and my bf. Always playing, eating well, we take him for walks in the parks. Last night the family who had him for a month came over, he was acting wild, biting, running, literally he went from 20% to 120% wild. he kept bitting the little kids while playing I know he didn't mean any harm. Usually he is calm...collected...he listens. We ended up scolding him. My hands were literally so badly scratched that I was embarrassed to go to work. I was blocking the kids little ffed from his bitting and ended up being hurt. After they left he became depressed completely ->ignored us. just went to a corner. this morning i left to work he seemed upset and my bf told me he ignored his callings, and just locked himself under my table. I came home earlier to check up on him he was joyful after i fed him he started to run right towards my hands and biting. Can anyone pls tell me what's wrong. My bf has been disciplining him on a daily basis since he got here. I tend to spoil him. thank you in advance. Do keep in mind this is our first dog, and it was unplanned we just didn't want him to change homes too much and decided to adopt. So we are not experts but I've been reading dozens of dog books and nothing worked so far.