That's rather normal behavior unfortunately.
In low light the camera needs to increase its light sensitivity by raising the ISO which in turn introduces digital noise. This makes the image appear grainy or fuzzy. The camera should have a night mode which would help with this, but it doesn't completely eliminate the problem.
When zooming if you go beyond 2X the phone is digitally zooming which in effect is just cropping the image resulting in fewer pixels and less detail. The telephoto lens for 2x zoom will also only work in adequate light. If there isn't enough light(typically outside daylight is required) it just digitally zooms the main camera.