GCSE stress and ICT ruining my reports

ICT was, at my school at least, a compulsory subject and so I am now in my second year of the Edexcel ICT course (Single, I believe).

The problem is, however, the stress. I'm finding the coursework really difficult, because I'm being forced to use software which - thanks to lousy teaching in my earlier years - I haven't a clue how to use. I'm earning a C in the coursework and my target grade overall for ICT (with the exams factored in also) is a B.

I consistently get A*s in the exams, so now my ICT teacher is expecting me to redo a large portion to average it out better and has been saying how I'm "slacking" in the coursework. The problem is, I barely know what I'm doing for a large portion of the tasks. Audacity, for example, is a really confusing piece of software to use blindly.

He keeps writing on reports about how I'm underperforming too. But, if I earn an A* in my exam and a high C in the coursework, that should average out to a B. I'm happy with that. He's expecting me to invest so much time into this coursework (I've literally spent hours at lunchtimes doing it) that I'm instead missing revision classes for my other subjects such as Science or Religion.

What can I do? It's seriously, as is all of my GCSEs really, stressing me out.