Army. Start and Stop Loving

I've only been dating my boyfriend for about 5 months and only meet him a month before dating. I'm 18 in high school still and he's 20 in th Army. Most of our relationship has been though hand written letters. I just saw him at his basic training graduation three months ago. I keep losing the feeling of love in us. Is it because I never get to talk/touch/see him? Everything is perfect! He's perfect! The only problem is we have to go though periods of time with no contact. It sucks but I never know where I'm thinking with him. Do I still love him is what I think to myself. Anyone else have done this where you start and stop this feeling? This also doesn't help that this is both of ours first real relationship. Thanks!