I hate when that happens! I use to have problems with Excel spreadsheets when I was teaching Excel, authoring a course in it. I think you need to back off a little on how much work you are doing, accept that you will do "fine" and "know" you can get As because you want to and will be able to make it happen now no matter what; relax a bit? I'd start reading some novels before bed or watching sit coms or something?