I don't think you're alone... so far you've always known what unit you've been working in, but now that we've covered a typical college semester at a high level, having things jumbled together isn't uncommon, especially after a long break. The good news -- we have one or two more days of material to cover, then we have a chance to sort everything out as we prepare for the mid-term. Take this time as an opportunity to clarify and organize your thoughts, to figure out your strengths and weaknesses -- then attack the weaknesses, and fortify the strengths.
You know more than you think you do... our first WebAssign practice MC test is designed to be a tough one... an exam to help you realize where you need to work -- but not in a comfortable way. Use it as it was intended -- a tool to help you focus your efforts moving forward. And if it rattled you a bit, perhaps that's not a bad thing either -- but don't let it throw you from your course!