It sounds as if you're really struggling with doing a business plan but it's great that you've made the commitment to do one.
A couple of tips that might help is that unless you're using the business plan to get financing from a bank, it really is something you're doing just for you
and your business. Don't worry so much about doing things right but concentrate more on what is right for your business. There also are some sites out there that offer simplified versions of business plans that also might be easier to help get you started.
There is also a thread here
about business plans, good luck!