You need to see your vet. Sounds like the bone may have caused some internal damage and rectal bleeding is no less serious in our pet's than it is in us. Shaking is probably from pain based on the information given.
My Dog Ate A Rib Bone,now Is Dripping Blood From The Rectum And Shaking,any Ideas?
Take him to the vet he could have swolled a piece whole and it got lodged or tore something