VR Mesh Falls Apart. Help Needed

I have this mesh that works in unreal (almost) perfectly. I have the mesh set up with an animation, which i have yet to add, but when i try to turn physics on for the mesh, anytime I am not holding the mesh is basically breaks apart into several pieces that stay in the same general area but are just broken. ( basically if i threw the mesh it would break in mid air instead of staying as one mesh but all the pieces would land in the same spot.) I’m not sure how to fix this in Blender where i made the mesh as it has multiple moving parts for the animation and if I joined all the vertices together the animation would make the mesh stretch in weird places. I’m sorry if this is a confusing problem. If images are needed i shall try to supply them.

The video is me making sure i never let go of the mesh. Again if needed I can take another video where i let go and the mesh falls apart. Ooblecks Weapon in Vr Test - YouTube