My best friend left for bootcamp for the marines about a week ago, and ever since then, I’ve been acting weird, both physically and emotionally. I can’t sleep, and when I do, it’s always nightmares about him dying on the battlefield.
I can’t eat, just thinking of food makes me sick to my stomach. I barely talk to any of my friends, and I’ve started to isolate myself from everyone. He’s all I think about day and night and I’ve ended up crying every night because I’m scared for him. But he’s my best friend, why am I acting this way?
LemonVibe 
Aw, it sounds like its such a difficult time!
I guess it’s natural to find it difficult when any close friend goes away – you’re bound to miss them and feel sad. Add to that the fact your friend has gone away to do something with heightened risk and danger, it’s totally understandable you feel so worried. It’s lovely you are so caring.
My advice would be to start doing all the stuff you’d normally be doing, if you weren’t feeling like this. E.g. You said you’ve isolated yourself from friends – it’s important to start seeing them again and doing things you enjoy. Even if it’s the last thing you feel like at first, the action comes before the feeling and you might find you start feeling better soon.
Right now, you’re worrying a lot and having so much time to dwell, because you’ve isolated yourself, is making the anxiety worse. But the thing is, whether you worry or not won’t change the outcome. It’s very likely, statistically, that your friend will be ok.
Look after yourself. X