Hello Element 5,
I would say what you feel is energy entering your body as part of the process of raising your vibration. I have had similar experiences in my sleep and it woke me up too - it's a very real experience. It's like energy gets inside the body and you can feel the vibration and tingling through every inch of the body. It's a great feeling. Sometimes a vision comes with the experience too. Sometimes there are certain events in life that triggers this vibrational shift. I don't know anything about animal spirits so I cannot comment about that part.