If you normally are regular with your periods, and you have missed one or more in a row, it usually would not be too early to test. It may be a combination of being ill (all over body hurting is not a sign of pregnancy), and perhaps stress about changes going to be taking place soon. Even if you are looking forward to joining the Army, it can still cause you some stress.
All you can do is wait a bit longer and try another test. You could wait and see if you miss your next expected period as well and test at that time to see if it may be just off cycle(s).
Good luck... and thank you ahead of time for your service with the Army!