As for the original question, I don’t think this is undoable (some of my friends and I are taking the same amount this year), but if you’re getting B’s with only two AP classes it will be difficult to keep up when you more than double that work. Especially since you’ll have to do a lot of writing to practice for some of the exams.
Also I agree with the above commenters about getting some calc experience if you plan to major in economics. At my school, stats is a semester course. Is it the same for you?