Workout, go have fun with friends, spend time with family. Honestly as great as these boards are they can build the anxiety and stress of waiting. Back in the dark ages when we got a letter that said our application was complete and we would hear by April 15th we just rolled with it. Luckily we didn't have all the social media and platforms to fuel the anxiety. We never hear from current 4/C that they wish they spent more time on these boards, but nearly all of them will say go have fun, spend time doing things with friends and family, enjoy senior year or college.
The military is full of huge waits. Branch night, duty stations, command selections, schools, more duty stations. All of them have huge implications to a career and become harder as you have families who are now impacted in many cases. I always say this is part of the training of learning to wait, because it's only the first of dozens to come.