this isn't pregnancy related but I need help!!!! I am making cakes and homemade frosting. well I ran…

this isn't pregnancy related but I need help!!!! I am making cakes and homemade frosting. well I ran out of powdered sugar so I blended my own. it seemed powdery enough so I mixed all of it together but now my frosting is all grainy like sugar!!!!!! I already tried reblending it, and it didn't work. what do I do to fix it!?