I have underestimated, too! I've never taken classes during the summer before (never needed to), and now I'm taking Psych and a math course. One is an 8 week course, and the other a 10 week course....
I'm in the same boat. I'm doing what OnOn2RN suggested, and taking courses that count toward a BSN while I'm waiting for the application period for Fall 2017. (Nutrition, Statistics,