Can't use the scale tool in Illustrator

Anna,

"When I make the illustration smaller as it is now, the lines don't shrink proportionately to the size of the illustration itself."

When you get unstuck from the current view, you can scale in different ways. Whichever way you choose, make sure to use Scale Strokes & Effects, in order to have the lines shrink.

You are in the Edit Toolbars mode, please select Window > Toolbars > Advanced to reset it.

Which tool are you trying to scale with? Because in your screenshot the magnifying glass is activated.

Transforming with the selection tools does not work if the selection frame is hidden with [Ctrl/Strg]+[Shift]+[B] - and this is how it looks in your screenshot.

Please post another screenshot with an existing selection and with the transform tool activated.