Sounds like where you are in life is challenging. Like, not everyone could endure the work you do. Add to that, some major setbacks in life, such as your love for your ex-gf. Tried to handle it a variety of ways, and still are feeling like your supervisor may be right about you. You are pretty sure that they are wrong, since you have proven yourself to be a good worker (soldier).
What is it about this girl that can not be found in any other? Have you fallen too far for real? Have you ever heard of someone who got married because they were "the one" only to discover otherwise later in life? Why is being reclusive for the time being so bad? Why does the supervisor's voice carry so much weight regarding you as a person?
I've been to hell (mentally) and back. I must say, many have thrown in the towel too soon. I never ever ever thought I would get better. Others got better, but never me. I have a strained relationship, few friends, and have learned to care (genuinely) little about the opinions of those who don't have my best interest in mind. I am a musician who has walked out on stage feeling like I wanted to *****, but the show must go on. Those of us who struggle with depression are anything but weak. Most would end their own life after a week. Depression is about losing friends, unfortunately. It all works out in time, though. Give it time.