Need Advice

I'm in a bit of a dilemma right now about how many courses to take this fall at school. I just decided to swap a class I was enrolled in on Modern French History (circa French Revolution) to a class called Deviance and Crime in the Sociology Department. I did this because my current internship has provoked my interest in crime and its sociology. I feel bad about dropping the French History class, which I wanted to take sophomore year, but at the same time I feel like I know more about French History than crime sociology because of my background in history and because I've already taken a European History class (granted that was high school, but it was a good class).

My other option is to take four classes, but I am only wary of that because I am starting my thesis next quarter which is accompanied by a mandatory Senior Thesis Seminar. I am also continuing French language class. So, I am only taking three classes, and my schedule is embarassingly light (one class each day except Thursday, when I have two classes, and NO CLASS on Friday). Maybe someone who's written a thesis or done independent study work or something can help me figure out whether that takes up so much time that balancing a fourth class would be difficult. I know a lot of people take 3, 2, or even 1 class while they're writing their thesis; at the same time, I'll be working on my thesis ALL SCHOOL YEAR (we don't start writing until the second quarter, I believe). That means I would take three quarters of three or fewer classes. This seems too easy now, but I don't know. In my favor, I've always taken four classes per quarter. So should I take four classes or three? Any suggestions? Your help will be received with tremendous gratitude.