<human>: I became very ill in 2008 (I was 18), and about 95% of my friends vanished from my life. People I loved, who had cried on my shoulders and myself on theirs. People I had spent my entire teenage life growing up with. People I thought were solid.

I was sick, and they vanished. The only people I apparently trust are the 2 friends who stuck with me, and my family.  And even those friends grew distant.  So it seem now, every time I get to caring about someone like that again, I see the relationship as if it's on a precipice, as if it could fall out from under me at any time, and I'll never see them again.

This is a girl I could marry.  But now this attitude I have is making me miserable, and could begin to interfere with our relationship.

How do I not feel like she's a mist that I never know when it will vanish?

Can you summarize the given text in a few sentences?
<bot>: got ditch by almost all my friends, now the fear of not getting ditched by the coolest girl I've ever met is making me miserable.