Very strange. Try selecting another unit of measurement from the ruler. Right click or control click on the ruler where you would normally get new guide lines. Then do it again. Setting the ruler to another measurement and back again sometimes fixes ruler strangeness. If that doesn't work you might have to trash your preferences.
I would say try saving the file doing a save as instead of a save and close and reopen it.
I that and or the other suggestion does not work try to place the file in a new empty document or copy and paste into a new empty document.
It sure looks like a corrupt file.
I don't have as new a version of Illustrator as you are working with, but at first glance I think I see where you are having a problem.
The "X:*******" field that you have highlighted in the Options Bar refers to the location of the Origin point ( of your orange rectangle. The Origin point is determined by the choice you have made in the little 3 X 3 matrix just to the left of "X:*******". The Origin point, as indicated by the values in the "X" & "Y" fields, is well off the active artboard area.
In other words...
The "X: -109.5903" —along with the "Y: -0.75"— does not indicate the SIZE of the rectangle, it indicates where the upper-left corner (which is shown in the matrix) is located. If you manually change the "X:********" & "Y:********" values so that the upper-left corner of your orange rectangle is located on the actual artboard, then you'll see that the size (indicated in the "W[idth]:______" & "H[eight]:_______" fields may not be what you expect them to be.
At least, I'm pretty sure that's where the problem is.
Hope that helps get you back on track.
I agree with Phos+four. The origin is set to be the fold line, hence all measurements will be negative in relation to it. Why you are getting wrong units, is another matter, but may simply depend on your content extending outside the view area and AI presenting screen coordinates ratehr then the physical units of the doc...