Your dreams 95% of the time reflect something that you are feeling in your waking world. Take the emotions in the dream and plug it back into your waking world and see the fit. Then, take the "things" in the dream and interpret it from there. When done, put the 2 interpretations and combine them and see the result.
Living in an old house (symbol of physical self/old meaning comfortable, wise, empowered) New dog (symbol for faithfulness, loyalty protection, friendship)"put my hand out" (open hand symbol of open to life, honesty) Dog: Your wise self said, "He looks new, but he is actually someone I have known before, and he will betray me, but just in case he isn't, I will extend my friendship." Of course, your wise self was correct.
There is someone/something who just entered your life that looks new and refreshing, but your wise self says, Don't trust him. He is a chameleon and in the end you will get hurt.(Bite off the hand that feeds you...)
It sounds like you have a very wise base from which to build your life. Trust your instincts. They will usually be right.