I'm afraid to be alone
I understand the feeling of being fearful of solitude. I have it pretty constantly, to the point where I just adopted a fourth house pet and am uncomfortable staying in any room without a radio or book-on-tape.
I know it's little help right now, while you're in what's clearly a BAD place, but maybe when you feel better, you can practice some strategies for feeling safe when you're alone. Something I've been doing lately is, thinking of all the friends or total strangers who are sending me good thoughts at the moment.
My friend who is a religious monotheist likes to draw emotional strength from all the thousands of people in her faith who are praying for the weak/lonely/sad at any given moment. If you are NOT religious, think instead about the thousands of people who are doing what's called a "Loving-Kindness" meditation right now. At any moment, tons of meditation practitioners are thinking kind, loving, caring thoughts and imagining that they're sending them to people like us, who need it. It doesn't matter that they don't know our names or we don't know theirs. What matters is that part of their practice is to CARE about every person who's suffering.
For me, personally, it makes me feel a little less alone. And, of course, there's this huge discussion board full of fellow anxiety-heads.