Take graphic design classes and work on portfolio pieces that bridge the gap.
Interior design sketches = do clean graphic design renderings of interior rooms and exterior buildings in different styles: vector, sketch, line art, color, black and white, iconographic.
Wallpaper selection = do graphic design renderings of abstract patterns that could resemble wallpaper designs but demonstrate graphical abilities balancing composition, shape, and color.
Industrial / commercial interior design = do graphic design renderings of signs for buildings that showcase their logos to demonstrate your abilities with creating logos and using typography.
What I've done is shown how elements of your schooling would translate to elements of graphic design, which are: visual renderings, abstract patterns, iconography, typography, color theory, composition.