Don't diminish who you are! I had an anatomy teacher who always made us draw diagrams of everything...bone structure, cell types, etc...She didn't criticize the lack of skill in any diagram. Just look at the illustrations in your book and do your best to draw them. In the process, you will find it helps you as you learn anatomy. And you will never be the only one who can't draw!
Try looking at pictures of animals for reference. Don't completely copy the picture, and make sure to give credit to the person who drew or took the picture.
