Layout and Spacing botched on Desktop vs. Laptop in 7.1

I am building a portfolio site but realized a couple days ago that the layout completely shifts between my mac pro and imac/desktop screens.  No matter what I do, the responsiveness just messes with the layout on both screens and I can't seem to adjust one without completely botching the other.  This is really disappointing as I've never had this problem with the old versions of SS.  Please help - trying to get this site up and running this week and this is the only thing stopping me from continuing to work on it.  Some older images attached. 

Please help asap if you can!  I am not a coder, but can inject code if provided and it doesn't mess with the rest of the site.  

I am building a portfolio site but realized a couple days ago that the layout completely shifts between my mac pro and imac/desktop screens.  No matter what I do, the responsiveness just messes with the layout on both screens and I can't seem to adjust one without completely botching the other.  This is really disappointing as I've never had this problem with the old versions of SS.  Please help - trying to get this site up and running this week and this is the only thing stopping me from continuing to work on it.  Some older images attached. 

Please help asap if you can!  I am not a coder, but can inject code if provided and it doesn't mess with the rest of the site.