Cardboard HUD

I'm trying to create a HUD which consists of a 2D gun image, using the Cardboard SDK.
However, this is what happens when I put a canvas with the image under the 'Head' GameObject of 'CardboardMain':


As you can see, by looking sideways it stays in its place, but when I look up or down it somehow moves.



As you can see in the above image, by looking up (or down) the distance between the canvas and the camera seems to increase. I guess this is what causes my issue. Any thoughts on this?

Help would be greatly appreciated!

Thanks for reading.

 

I am using the same trick of a 2D gun object, but didn't encounter your issue.

Here is how I did it (I don't know if it's the best way but it's works, and I am open to critics):
-I put my HUD in the MainCamera object
-I didn't use canvas, only spriteRenderer

 

Welp, it seems this was caused by me setting the scale of my CardboardMain object to (x,y,z): (1,2,1).