So I used NURBS curves to make an object (In 2D), but how do I make it 3D?

Right, so I used the ‘extrude’ option for curve to extrude my object (Which I had filled in using Alt + C ) so it would look 3D, but now I actually want it to be 3D. Because its still sort of like a 2D surface, so I cannot select a face, line, or point at all.

I need it to be changed into a 3D object, the problem is that when I hit the button ‘3D’ for the shape. It removes the fill that made the shape how I wanted it to be. And its empty in the middle…

Help.:spin:

Alt+C - convert to mesh from curve

Thank you so much Richard