How to get my puppy to stop being mad at me?

My puppy is about 8 months old. The most I ever left him completely alone was from maybe 10a.m. to 10p.m. He has a big fenced circle that he stays in daily(size of One and a half Xlarge carrying cases and he fits in the smallest carrying case). He takes care of himself eating,drinking pottying on his matt,but i do take him outside daily for at least 15 minutes. Whenever my puppy is home alone he never eats and barely drinks.Thats pretty normal,but usually when i get home he licks me,plays with me,and snuggles.This time he was SUPER bitey(usually teeths alittle but this was not usual) I held him and wouldnt lick me,and wouldnt let me snuggle or play with him. I Only Left for 2 days but left two bowls of water two bowls of food,toys and some treatS(the treats were gone before i even left the house but when i returned it seemed not a bit of food was eaten and the only slightest of water was drained). I love my dog so please help me!?