supplements won't do anything for your testosterone during these 4 months. just make sure you eat enough to recover (make sure you get enough fat), sleep 7 hours a night (non-negotiable, I was also in an academy and sleep debt is the biggest issue), and do stress-relieving things when away from the academy (hang out with family/friends, do mindfulness meditation, go to the movies, etc). watch out for excess caffeine - it has been shown to increase stress even more on top of already stressful activities. you also want sleep quality, which caffeine can affect greatly.
make sure you lift 2-4 x a week depending on how you feel and how active you were in the academy. you want to maintain what muscle you have. No more than an hour in the gym, and take plazma + creatine.