Blender animation breaks after importing to Unity and switching to Humanoid rig

I'm trying to make a basic prone animation for my first game. The idle animation only has the character still, but breathing slightly. The hands and legs, (which should be completely still) sway left and right with the rest of the animation.

In Blender, I've made a custom IK rig out of the same character. It has the same armature with the same bones in the same order, I just added IK bones to make it easy to animate. I export with these settings:

-Selected Objects
-Apply Transform
-Only Deform Bones
-Bake Animation
-Key All Bones
-Force Start/End Keying
-NLA Strips OFF
-All Actions OFF

I have also baked the animation, with these settings:

-Only Selected Bones
-Visual Keying
-Overwrite Current Action
-Bake Every Frame
-Clean Curves

I don't know what im doing wrong. It's as if my entire model is swaying left and right around the center, where the hips are. It works perfectly fine in Generic, but when I make the rig Humanoid, that's when it breaks.