Fallen off the Wagon

I feel ya, university finals are killer for my motivation to work out and I inevitably end up snacking more and eating treats as rewards for crushing exams/papers/presentations. I like to go to my school's gym after each final (I had 5 this semester) unless I have one the next day.
Keeping carrot sticks, cumber slices, or sugar peas in the fridge is a good option for mindless boredom snacking instead of popcorn or chips or chocolates etc. I also drink copious amounts of green tea without sugar. In high school I stopped adding sugar to tea/coffee cold turkey unless it is a drink from a cafe, then it is a treat and I always use skim milk when I do add milk to Earl Grey or various Chais. It is hard but give it time! It actually makes me feel sick if I add sugar to tea now, but I do prefer sweetened coffee, a drop of honey is decent and soothing.
Sneaking out for walks as a study break with lecture recordings on your music player or phone is a good way of still studying but fitting in some relaxing fresh air exercise. I also like to take leisurely study blocks on a yoga mat and stretch and skim notes at the same time. Honestly, it is a few weeks of your life and although it sucks and it feels bad or induces guilt to get off the wagon for a bit, school is most important and your good habits are hopefully already well ingrained in your day-to-day routine so you will bounce back on track when the stress of school fades for the summer.
Good luck!