Fbx export not working

I am trying to export a model with animations as a fbx so i can use it in unity. But blenders fbx export just acts really weird. I tried to export as a FBX 7.4 and a FBX 6.1 and they both give me differed problems. the 7.4 model is not skinned correctly because the foot of the character detaches from the body in the run cycle. the 6.4 model has the eyes not animated correctly, the eyes are a separate model but skinned to the same armature as the body. I tried to join the eyes to the body but this gives loads of other problems. I also tried to drag the .blend file in unity but this gives the same problems.

why is blender fucking up my animations? it really pisses me off because i am trying to solve this problem for days now and it just doesn’t make sense to me. everything is working fine in the project itself.