4month old chihuahua x maltese

[rickypuppy]

I have a 4 month old puppy named ricky his chihuahua x maltese. very small in size but big ego. He is toilet trained although we have accidents here and there and for some reason likes to do his business on carpet my apartment is mainly tiles but carpet in hallway. He also has a problem with getting excited when people come over, he sprinkles everywhere once he is greeted. If he doesn't know the guest then he barks until they pat him and usually guards my husband and i. He gets lots of exercise and play, the neighbour's two dogs he plays with everyday and he isn't the most confident dog one is a basset hound and the other is a beagle puppy only 8 week old. He doesn't appear to be scared but he seems uninterested, i dont know how to make him more socialable. He gets stressed when my husband leaves for work or leaves to go out, Ive noticed he ripps the kitchen mat, which i can assume is stress. He doesn't like to be alone he cries, barks ands howls but not for too long. I want him to be a good dog around people and other dogs. ive had dogs before but everything i try dodesnt work everyone says its because his hyper and still a puppy but i know he has it in him. Any help???