Always craving chocolate and sugary things

Hello FB fam! Does anyone have any tips to reduce sugar cravings? During my exam time I'm always (and I do mean always) craving sugary food. Especially chocolate. I don't mind treating myself once in a while but the problem is once I have one or two bars I have to have the rest too! Then I end up feeling guilty and saying "What the heck might as well eat unhealthy all day." Not the best mindset but I can't seem to get rid of it.