In 1970 I changed my major from history to sociology, just before my senior year (with only one sociology course to my credit -- I graduated with more history credits, my new minor, than sociology). Around 2001 I was thinking about what I would regret when I was really old and wondered about where my love of history went so went back and got a second degree, in history (2007) and then went on and got a degree from Oxford just a year ago, so I can appreciate how hard you have worked. I too was in my history groups/clubs and had a 4.0 GPA, the whole nine yards of participation.

Were I you, now, I would take my year off and jump through the hoops to become a certified genealogist: http://www.bcgcertification.org/ I don't know what field of history you were interested in and if social history is a good fit for you but I find it very satisfying. There are many magazines to write for and zillions of groups and lecture opportunities and it would give you a focus for your further academic work toward a PhD and professorship.

Good online program to get you started: Genealogical Research Program Classroom and Online | Center for Professional Education | Boston University