Hi,
Please do not worry, similar has happened at my school before I know for a fact. It depends on your reasoning, usually reasons such as serious illness give a small amount of extra marks. I am sure in your case it would, but you can get external examiners to mark the work if this is a problem with your school. Art coursework really depends on dedication towards your work, I know that is hard, I am completing mine too! Please do never think your work is rubbish, art is very subjective and in this way can have serious implications.
My tips for your course work is...
1. Look over what work you have, does it link through to the original idea eg.habitat? Make your work flow through your thought process.
2. Use a variety of mediums. The main 3 to focus on for me is pen, pencil, and ink. Annotations should highlight media and what experience you have with it.
3. My work so far is the following, even if you add one drawing per section to a board, it will help you greatly.
Moodboard
Artist study- draw one of their pictures and incorporate their style or ideas into your work.
Ideas- sketch some rough drawings of one or 2 concepts
Photoshoot- take some quick pictures and draw one of them to show how you learn about, for example, form
Media- what will you use for your final idea- ink, pencil etc.
Composition- where will everything be placed, what colour is most impacting...
Outcome- a final outcome to your project- what all your work has led up to
Hope this helps and have a good week