Bought 2 guinea pigs my dogs going crazy?

We bought 2 guinea pigs recently and because we have 3 rabbits our dog gets along with them, my dogs a king charles cavalier spaniel very calm and friendly, but ever since we got the guinea pigs hes gone nuts, i held my guinea pig put it back in the cage and he was going crazy thinking i still had it. What should i do and why is he being like this?