Locking a background layer when creating a form

I am really hoping someone can help me before I lose all my hair! 😞 I am making an editable homeschool planner for my shop.  I have made forms before and am pretty familiar with it, but I have never made one with quite so many pags before.  

I am running into a major issue every time I try to create form fields for a calendar on one of the pages.  While I am trying to move form fields to adjust their position or size,  sometimes I accidently click off of the form field and the result is that it shifts the background image and ultimately messes it all up.  If I don't notice it right away, then I have to go back in and re-add the page and start all over.  I am out of ideas.  I have tried opening the psd in illustrator and extracting it as an interactive PDF so that I can lock the layer, but it still moves stuff on the background.  

What I am doing wrong? 

Here is an example of what the issue is: