Or, just don't do much drawing. Okay so I'm sure it would help to be able to draw, but take advantage of what you're good at. You say you're good at sculpting? Sculpt.

Now that I look back on my GCSE Art, I really didn't do that much drawing.

When you leave school, do you plan on going to college? If so, and you plan on doing a specialized course (not A levels) do one that involves what you are skilled with. Same with University, if you plan on going to that.